Semiconductor device and electronic device

ABSTRACT

A high-frequency signal from a tape-shaped line section having a surface layer signal lead and surface layer GND lead disposed on both sides thereof is directly inputted to a semiconductor chip via a signal surface layer wiring of a package substrate and through solder bump electrodes. Alternatively, a high-frequency signal from the semiconductor chip is outputted to the outside via the tape-shaped line section in reverse. Owing to the transmission of the high-frequency signal by only a microstrip line at the whole surface layer of the package substrate, the high-frequency signal can be transmitted by only the microstrip line at the surface layer without through vias or the like. Accordingly, the high-frequency signal can be transmitted without a loss in frequency characteristic, and a high-quality high-frequency signal can be transmitted with a reduction in loss at high-frequency transmission.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device and anelectronic device, and particularly to a technology effective forapplication to transmission of a high-frequency signal.

There has heretofore been known a structure having adopted a coaxialcable as high-speed signal transmission means. A semiconductor package(semiconductor device) of a PGA (Pin Grid Array) type makes use of acoaxial cable as a signal transmission path extending in its thicknessdirection between a part packaging surface of a multilayered wiringboard and its back surface (see the following patent document 1, forexample).

There has been also known one wherein a coaxial cable is used in anoptical communication apparatus (see the following non-patent document1, for example).

Patent document 1:

Unexamined Patent Publication No. Hei 5(1993)-167258 (FIG. 1)

Non-patent document 1:

“Various Characteristics of 565 Mb/s Optical Transmitter Using DFB-LD”by Shoichi Hanaya, Katsuyoshi Karasawa, Kichi Yamashita, and MinoruMaeda, National Meeting of Communication, Optical and Radio Departments,Published in Sep. 3, 1986 (Showa 61) (pp 2-170, FIG. 2)

SUMMARY OF THE INVENTION

The input/output of a signal to a semiconductor package has heretoforebeen performed via “wirings”. However, a problem arises in that with theoperation of a semiconductor chip mounted on the semiconductor packagein a high-frequency region, the efficiency of propagation of the signalis degraded if no suitable wiring structure design is carried out, thuscausing degradation in high-frequency characteristics.

In the PGA type semiconductor package having adopted the coaxial cable,a core line of the coaxial cable and its corresponding surface wiring ofthe multilayered wiring board are bonded to each other in a state ofbeing struck at right angles. The difference in sectional area as viewedin a direction normal to a core-line extending direction between thecore line and the surface wiring is large. Therefore, the signal isreflected by a spot where the area of a bonding portion of the core lineand the surface wiring changes.

As a result, a problem arises in that the high-frequency characteristicsare degraded.

The present inventors have discussed, as a structure for realizing ahigh-frequency semiconductor device connected to a coaxial cable, astructure wherein inner leads are connected to a package substrate witha high-frequency semiconductor chip mounted thereon, as externalconnecting terminals thereof, and outer leads respectively coupled tothe inner leads protrude from the package substrate to the outsidethereof along a plane direction thereof.

However, the structure wherein the outer leads protrude outwardly of thepackage substrate along the plane direction thereof, is accompanied by aproblem that its size reduction cannot be achieved.

An object of the present invention is to provide a semiconductor deviceand an electronic device which improve the quality of high-frequencycharacteristics.

Another object of the present invention is to provide a semiconductordevice and an electronic device both of which can be downsized.

A further object of the present invention is to provide a semiconductordevice and an electronic device both of which can be thinned.

A still further object of the present invention is to provide asemiconductor device and an electronic device both of which can bereduced in cost.

The above, other objects and novel features of the present inventionwill become apparent from the description of the present specificationand the accompanying drawings.

A summary of a typical one of the inventions disclosed in the presentapplication will be described in brief as follows:

The present invention provides a semiconductor device comprising awiring board formed with a surface layer wiring, a semiconductor chipelectrically connected to and mounted on the wiring board, a pluralityof external connecting terminals provided within either a main surfaceof the wiring board or a back surface thereof opposite to the mainsurface, and a transmission line section electrically connected to thesurface layer wiring of the wiring board, wherein at least either inputor output of a signal to the semiconductor chip is performed through thetransmission line section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing one example of a structure of asemiconductor device (high-frequency package) according to a firstembodiment of the present invention;

FIG. 2 is an external perspective view illustrating one example of astructure of an optical module with the high-frequency package shown inFIG. 1 built therein;

FIG. 3 is a cross-sectional view depicting the structure of the opticalmodule shown in FIG. 2;

FIG. 4 is a plan view showing one example of a layout of parts built inthe optical module shown in FIG. 2;

FIG. 5 is a cross-sectional view illustrating one example of the layoutof the parts built in the optical module shown in FIG. 2;

FIG. 6 is a cross-sectional view showing a structure of a semiconductordevice (high-frequency package) according to a modification of the firstembodiment of the present invention;

FIG. 7 is a partly plan view illustrating one example of a structure ofa microstrip line of a wiring board employed in the high-frequencypackage shown in FIG. 1;

FIG. 8 is a partly cross-sectional view showing the structure of themicrostrip line shown in FIG. 7;

FIG. 9 is a partly plan view depicting a structure of a microstrip lineillustrative of a modification of the microstrip line of the wiringboard employed in the high-frequency package shown in FIG. 1;

FIG. 10 is a partly cross-sectional view showing the structure of themicrostrip line illustrative of the modification shown in FIG. 9;

FIG. 11 is a perspective view and a cross-sectional view showing astructure of a semiconductor device (high-frequency package)illustrative of another modification of the first embodiment of thepresent invention;

FIG. 12 is a cross-sectional view depicting one example of a cap-mountedstructure of the high-frequency package shown in FIG. 1;

FIG. 13 is a plan view of the cap-mounted structure shown in FIG. 12;

FIG. 14 is a cross-sectional view showing a structure of a cross-sectioncut along line A—A of FIG. 13;

FIG. 15 is a bottom view of the cap-mounted structure shown in FIG. 13;

FIG. 16 is a plan view showing one example of the relationship ofposition between surface layer wirings and a cap employed in thecap-mounted structure shown in FIG. 12;

FIG. 17 is a bottom view illustrating a structure of the cap as seen inthe direction indicated by an arrow C of FIG. 14;

FIG. 18 is a side view showing the structure of the cap shown in FIG.17;

FIG. 19 is a cross-sectional view illustrating the structure of the capshown in FIG. 17 and an enlarged partly cross-sectional view of itscorner;

FIG. 20 is an enlarged partly cross-sectional view showing a detailedstructure of the cross-section cut along line A—A of FIG. 13;

FIG. 21 is an enlarged partly cross-sectional view illustrating adetailed structure of a cross-section cut along line B—B of FIG. 13;

FIG. 22 is an enlarged partly plan view showing one example of therelationship of position between the surface layer wirings employed inthe cap-mounted structure shown in FIG. 12 and an opening of the capemployed therein;

FIG. 23 is a cross-sectional view illustrating a structure of asemiconductor device (high-frequency package) illustrative of a furthermodification of the first embodiment of the present invention;

FIG. 24 is an enlarged partly cross-sectional view showing one exampleof a structure wherein a radiating member is mounted to the cap shown inFIG. 12;

FIG. 25 is a cross-sectional view depicting a structure of asemiconductor device (high-frequency package) illustrative of a stillfurther modification of the first embodiment of the present invention;

FIG. 26 is a cross-sectional view showing a structure of a semiconductordevice (high-frequency package) illustrative of a still furthermodification of the first embodiment of the present invention;

FIG. 27 is a cross-sectional view depicting a structure of asemiconductor device (high-frequency package) illustrative of a stillfurther modification of the first embodiment of the present invention;

FIG. 28 is a plan view showing a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 29 is a cross-sectional view illustrating the structure of thehigh-frequency package shown in FIG. 28;

FIG. 30 is a plan view showing a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 31 is a plan view depicting a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 32 is a plan view showing a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 33 is a plan view depicting a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 34 is a cross-sectional view showing the structure of thehigh-frequency package illustrated in FIG. 33;

FIG. 35 is a plan view depicting a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 36 is a cross-sectional view showing the structure of thehigh-frequency package depicted in FIG. 35;

FIG. 37 is a plan view depicting a structure of a semiconductor device(high-frequency package) illustrative of a still further modification ofthe first embodiment of the present invention;

FIG. 38 is a cross-sectional view showing the structure of thehigh-frequency package illustrated in FIG. 37;

FIG. 39 is a cross-sectional view showing a structure of a semiconductordevice (high-frequency package) according to a second embodiment of thepresent invention;

FIG. 40 is a cross-sectional view showing a structure of a semiconductordevice (high-frequency package) illustrative of a modification of thesecond embodiment of the present invention;

FIG. 41 is a cross-sectional view depicting a structure of asemiconductor device (high-frequency package) illustrative of anothermodification of the second embodiment of the present invention;

FIG. 42 is a cross-sectional view showing one example of a state inwhich a cap is mounted upon assembly of the high-frequency package shownin FIG. 41;

FIG. 43 is a partly cross-sectional view depicting one example of astate in which an auxiliary substrate and a coaxial cable are connectedto each other upon assembly of the high-frequency package shown in FIG.41;

FIG. 44 is a partly cross-sectional view showing one example of atesting state at the assembly of the high-frequency package shown inFIG. 41;

FIG. 45 is a partly cross-sectional view depicting one example of astructure subsequent to the completion of assembly of the high-frequencypackage shown in FIG. 41;

FIG. 46 is a plan view showing one example of a layout of parts built inan optical module according to a third embodiment of the presentinvention;

FIG. 47 is a cross-sectional view illustrating one example of the layoutof the parts built in the optical module shown in FIG. 46;

FIG. 48 is a cross-sectional view showing a modification of a connectingmethod of a transmission line section employed in the optical moduleshown in FIG. 46;

FIG. 49 is a plan view depicting a layout of parts built in an opticalmodule illustrative of a modification of the third embodiment of thepresent invention;

FIG. 50 is a cross-sectional view showing one example of the layout ofthe parts built in the optical module shown in FIG. 49;

FIG. 51 is a plan view illustrating a structure of a tape-shapedtransmission line section showing one example of the transmission linesection employed in the third embodiment of the present invention;

FIG. 52 is a cross-sectional view showing a structure of a cross-sectioncut along line A—A shown in FIG. 51;

FIG. 53 is a cross-sectional view illustrating a structure of across-section cut along line B—B shown in FIG. 51;

FIG. 54 is a back view showing a structure of a back surface of thetape-shaped transmission line section shown in FIG. 51;

FIG. 55 is a cross-sectional view illustrating a structure of across-section cut along line C—C shown in FIG. 51;

FIG. 56 is a plan view showing a structure of a tape-shaped transmissionline section illustrative of a modification of the third embodiment ofthe present invention;

FIG. 57 is a cross-sectional view illustrating a structure of across-section cut along line A—A shown in FIG. 56;

FIG. 58 is a cross-sectional view showing a structure of a cross-sectioncut along line B—B shown in FIG. 56;

FIG. 59 is a back view depicting a structure of a back surface of thetape-shaped transmission line section shown in FIG. 56;

FIG. 60 is a cross-sectional view illustrating a structure of across-section cut along line C—C shown in FIG. 56;

FIG. 61 is a plan view showing a structure of a tape-shaped transmissionline section illustrative of another modification of the thirdembodiment of the present invention;

FIG. 62 is a cross-sectional view depicting a structure of across-section cut along line A—A shown in FIG. 61;

FIG. 63 is a cross-sectional view showing a structure of a cross-sectioncut along line B—B shown in FIG. 61;

FIG. 64 is a back view showing a structure of a back surface of thetape-shaped transmission line section shown in FIG. 61;

FIG. 65 is a cross-sectional view illustrating a structure of across-section cut along line C—C shown in FIG. 61;

FIG. 66 is a cross-sectional view showing one example of a mountingstructure of a high-frequency package provided with the tape-shapedtransmission line section according to the third embodiment of thepresent invention;

FIG. 67 is an enlarged partly cross-sectional view showing, in adeveloped form, a structure of a portion D shown in FIG. 66;

FIG. 68 is a cross-sectional view illustrating a structure of across-section cut along line E—E shown in FIG. 67;

FIG. 69 is a cross-sectional view showing a modification of thestructure shown in FIG. 68;

FIG. 70 is a cross-sectional view illustrating a modification of thestructure shown in FIG. 66;

FIG. 71 is a cross-sectional view showing another modification of thestructure shown in FIG. 66;

FIG. 72 is a plan view showing a structure of a tape-shaped transmissionline section illustrative of a further modification of the thirdembodiment of the present invention;

FIG. 73 is a plan view showing a connected state of the tape-shapedtransmission line section illustrative of the modification shown in FIG.72;

FIG. 74 is a cross-sectional view showing a mounting structure of astill further modification of the tape-shaped transmission line sectionaccording to the third embodiment of the present invention;

FIG. 75 is a cross-sectional view illustrating a mounting structure of astill further modification of the tape-shaped transmission line sectionaccording to the third embodiment of the present invention;

FIG. 76 is a perspective view showing one example of a structure of ahigh-frequency package according to a fourth embodiment of the presentinvention;

FIG. 77 is a plan view illustrating the structure of the high-frequencypackage shown in FIG. 76;

FIG. 78 is a perspective view showing a structure of a back side of aframe-shaped transmission line section mounted to the high-frequencypackage shown in FIG. 76;

FIG. 79 is a cross-sectional view depicting one example of a mountingstructure of the high-frequency package shown in FIG. 76;

FIG. 80 is a plan view showing a structure of a high-frequency packageillustrative of a modification of the fourth embodiment of the presentinvention;

FIG. 81 is a perspective view illustrating the structure of thehigh-frequency package shown in FIG. 80;

FIG. 82 is a perspective view showing a structure of a back side of atransmission line section mounted to the high-frequency package shown inFIG. 81;

FIG. 83 is a plan view depicting a structure of a high-frequency packageillustrative of another modification of the fourth embodiment of thepresent invention;

FIG. 84 is a perspective view showing the structure of thehigh-frequency package shown in FIG. 83;

FIG. 85 is a perspective view illustrating a structure of a back side ofa transmission line section mounted to the high-frequency package shownin FIG. 84;

FIG. 86 is a cross-sectional view showing the structure of thehigh-frequency package shown in FIG. 83;

FIG. 87 is a plan view illustrating a structure of a tape-shapedtransmission line section according to a fifth embodiment of the presentinvention;

FIG. 88 is a plan view showing a structure of a base metal layer of thetape-shaped transmission line section shown in FIG. 87;

FIG. 89 is a plan view depicting a structure of an insulating layer ofthe tape-shaped transmission line section shown in FIG. 87;

FIG. 90 is a plan view illustrating a structure of a surface-layer metallayer of the tape-shaped transmission line section shown in FIG. 87;

FIG. 91 is a plan view showing a structure of a cover coat layer of thetape-shaped transmission line section shown in FIG. 87;

FIG. 92 is a cross-sectional view illustrating a structure of across-section cut along line A—A shown in FIG. 87;

FIG. 93 is a cross-sectional view depicting a structure of across-section cut along line B—B shown in FIG. 87;

FIG. 94 is a partly cross-sectional view showing a connecting structureof the base metal layer of the tape-shaped transmission line sectionshown in FIG. 87;

FIG. 95 is a partly cross-sectional view illustrating a connectingstructure of the surface-layer metal layer of the tape-shapedtransmission line section shown in FIG. 87;

FIG. 96 is a plan view depicting a structure of a tape-shapedtransmission line section illustrative of a modification of the fifthembodiment of the present invention;

FIG. 97 is a plan view showing a structure of a base metal layer of thetape-shaped transmission line section shown in FIG. 96;

FIG. 98 is a plan view illustrating a structure of an insulating layerof the tape-shaped transmission line section shown in FIG. 96;

FIG. 99 is a plan view depicting a structure of a surface-layer metallayer of the tape-shaped transmission line section shown in FIG. 96;

FIG. 100 is a plan view showing a structure of a cover coat layer of thetape-shaped transmission line section shown in FIG. 96;

FIG. 101 is a cross-sectional view illustrating a structure of across-section cut along line A—A shown in FIG. 96;

FIG. 102 is a cross-sectional view depicting a structure of across-section cut along line B—B shown in FIG. 96;

FIG. 103 is a partly cross-sectional view showing a connecting structureof a surface-layer metal layer (GND) of the tape-shaped transmissionline section shown in FIG. 96;

FIG. 104 is a partly cross-sectional view illustrating a connectingstructure of a surface-layer metal layer (signal) of the tape-shapedtransmission line section shown in FIG. 96;

FIG. 105 is a cross-sectional view showing a structure of a tape-shapedtransmission line section illustrative of another modification of thefifth embodiment of the present invention;

FIG. 106 is a plan view depicting a structure of a tape-shapedtransmission line section illustrative of a further modification of thefifth embodiment of the present invention;

FIG. 107 is a plan view showing a structure of a tape-shapedtransmission line section illustrative of a still further modificationof the fifth embodiment of the present invention;

FIG. 108 is a plan view showing one example of a connecting structure ofthe tape-shaped transmission line section according to the fifthembodiment of the present invention;

FIG. 109 is a plan view showing one example illustrative of how a returncurrent flows in the connecting structure shown in FIG. 108; and

FIG. 110 is a plan view showing how a return current flows in aconnecting structure of a comparative example with respect to theconnecting structure shown in FIG. 108.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will hereinafter bedescribed in detail with reference to the accompanying drawings.

Whenever circumstances require it for convenience in the followingembodiments, they will be described while being divided into a pluralityof sections or embodiments. However, unless otherwise specified inparticular, they are not irrelevant to one another. One thereof has todo with modifications, details and supplementary explanations of some orall of the other.

When reference is made to the number of elements or the like (includingthe number of pieces, numerical values, quantity, range, etc.) in thefollowing embodiments, the number thereof is not limited to a specificnumber and may be greater than or less than or equal to the specificnumber unless otherwise specified in particular and definitely limitedto the specific number in principle.

It is also needless to say that components (including element or factorsteps, etc.) employed in the following embodiments are not alwaysessential unless otherwise specified in particular and considered to bedefinitely essential in principle.

Similarly, when reference is made to the shapes, positional relationsand the like of the components or the like in the following embodiments,they will include ones substantially analogous or similar to theirshapes or the like unless otherwise specified in particular andconsidered not to be definitely so in principle, etc. This is similarlyapplied even to the above-described numerical values and range.

Members each having the same function in all the drawings for describingthe embodiments are respectively identified by the same referencenumerals and their repetitive description will therefore be omitted.

(First Embodiment)

FIG. 1 is a cross-sectional view showing one example of a structure of ahigh-frequency package according to a first embodiment of the presentinvention, FIG. 2 is an external perspective view illustrating oneexample of a structure of an optical module with the high-frequencypackage shown in FIG. 1 built therein, FIG. 3 is a cross-sectional viewdepicting the structure of the optical module shown in FIG. 2, FIG. 4 isa plan view showing one example of a layout of parts built in theoptical module shown in FIG. 2, FIG. 5 is a cross-sectional viewillustrating one example of the layout of the parts built in the opticalmodule shown in FIG. 2, FIG. 6 is a cross-sectional view showing astructure of a high-frequency package according to a modification of thefirst embodiment, FIG. 7 is a partly plan view illustrating one exampleof a structure of a microstrip line of a wiring board employed in thehigh-frequency package shown in FIG. 1, FIG. 8 is a partlycross-sectional view showing the structure of the microstrip line shownin FIG. 7, FIG. 9 is a partly plan view depicting a structure of amicrostrip line illustrative of a modification of the microstrip line ofthe wiring board employed in the high-frequency package shown in FIG. 1,FIG. 10 is a partly cross-sectional view showing the structure of themicrostrip line illustrative of the modification shown in FIG. 9, FIG.11 is a perspective view and a cross-sectional view showing a structureof a high-frequency package illustrative of another modification of thefirst embodiment, FIG. 12 is a cross-sectional view depicting oneexample of a cap-mounted structure shown in FIG. 1, FIG. 13 is a planview of the cap-mounted structure shown in FIG. 12, FIG. 14 is across-sectional view cut along line A—A of FIG. 13, FIG. 15 is a bottomview of the cap-mounted structure shown in FIG. 13, FIG. 16 is a planview showing one example of the relationship of position between surfacelayer wirings and a cap employed in the cap-mounted structure shown inFIG. 12, FIG. 17 is a bottom view illustrating a structure of the cap asseen in the direction indicated by an arrow C of FIG. 14, FIG. 18 is aside view showing the structure of the cap shown in FIG. 17, FIG. 19 isa cross-sectional view illustrating the structure of the cap shown inFIG. 17 and an enlarged partly cross-sectional view of its corner, FIG.20 is an enlarged partly cross-sectional view cut along line A—A of FIG.13, FIG. 21 is an enlarged partly cross-sectional view cut along lineB—B of FIG. 13, FIG. 22 is an enlarged partly plan view showing oneexample of the relationship of position between the surface layerwirings employed in the cap-mounted structure shown in FIG. 12 and anopening of the cap employed therein, FIG. 23 is a cross-sectional viewillustrating a structure of a high-frequency package illustrative of afurther modification of the first embodiment, FIG. 24 is an enlargedpartly cross-sectional view showing one example of a structure wherein aradiating member is mounted to the cap shown in FIG. 12, FIGS. 25, 26and 27 are respectively cross-sectional views depicting structures ofhigh-frequency packages illustrative of still further modifications ofthe first embodiment, FIG. 28 is a plan view showing a structure of ahigh-frequency package illustrative of a still further modification ofthe first embodiment, FIG. 29 is a cross-sectional view of thehigh-frequency package shown in FIG. 28, FIGS. 30, 31 and 32 arerespectively plan views showing structures of high-frequency packagesillustrative of still further modifications of the first embodiment,FIG. 33 is a plan view depicting a structure of a high-frequency packageillustrative of a still further modification of the first embodiment,FIG. 34 is a cross-sectional view of the high-frequency packageillustrated in FIG. 33, FIG. 35 is a plan view depicting a structure ofa high-frequency package illustrative of a still further modification ofthe first embodiment, FIG. 36 is a cross-sectional view of thehigh-frequency package depicted in FIG. 35, FIG. 37 is a plan viewdepicting a structure of a high-frequency package illustrative of astill further modification of the first embodiment, and FIG. 38 is across-sectional view of the high-frequency package illustrated in FIG.37, respectively.

The semiconductor device according to the first embodiment shown in FIG.1 is a semiconductor package equipped with an optical communication IC(Integrated Circuit), e.g., a high-frequency package 1 capable ofperforming high-speed transmission at 40 Gbps. Incidentally, thehigh-frequency package 1 is mounted to an optical module (an electronicdevice such as a semiconductor module device) 14 shown in FIGS. 2 and 3and has a coaxial cable 7 used as one for signal transmission on thehigh-frequency side.

Now, the coaxial cable 7 employed in the first embodiment is one exampleof a transmission line. Incidentally, the transmission line is a wiringpath for transmitting high frequency power, such as a microstrip line, afeeder cable or the like. A general wiring is a line for transmittingpower regardless of high and low frequencies. While an input portionthereof and an output portion thereof are electrically connected to eachother, characteristics at the transmission of the power are notnecessarily taken into consideration. Accordingly, there may be a casein which high frequency power is not transmitted (the output is zero)even though low frequency power is transmitted.

On the other hand, the transmission line is of a line wherein wiringshapes or configurations and configurations and layouts of peripheralconductors including wirings, the quality of a material for aninsulating layer, and the thickness and structure of the insulatinglayer are designed in such a manner that power is propagated withefficiency without a substantial reduction in output due to attenuationand reflection of the power in the course of its propagation.

The high-frequency package 1 according to the first embodiment comprisesa package substrate (wiring board) 4 used as a chip carrier having amicrostrip line 4 g made up of a signal surface layer wiring (surfacelayer wiring) 4 c and GND layers (ground conductor layers) 4 f formedinside through the signal surface layer wiring 4 c and an insulatinglayer 4 e, a high-frequency semiconductor chip 2 electrically connectedto and mounted onto a main surface 4 a of the package substrate 4 byflip-chip connection with a plurality of solder bump electrodes 5interposed therebetween, a coaxial cable 7 whose core line 7 a iselectrically connected to the signal surface layer wiring 4 c, anunderfill resin 6 poured between a main surface 2 a of the semiconductorchip 2 and the main surface 4 a of the package substrate 4 to protectthe flip-chip connected portion, and ball electrodes 3 used as aplurality of external connecting terminals disposed within a backsurface 4 b located on the side opposite to the main surface 4 a of thepackage substrate 4.

Namely, the high-frequency package 1 is one wherein a signal of a highfrequency (e.g., 40 Gbps) inputted from the coaxial cable 7 is directlyinputted to the semiconductor chip 2 so as to propagate through thesolder bump electrodes 5 via the signal surface layer wiring 4 c of thepackage substrate 4. The high-frequency package 1 has a structurewherein the high-frequency signal can be transmitted by only themicrostrip line at the whole surface layer of the package substrate 4.

Owing to the transmission of the high-frequency signal by only themicrostrip line at the surface layer of the package substrate 4 withoutthrough via-based wirings or the like, the high-frequency signal can bethus transmitted without a loss in frequency characteristic.

Namely, vias (also including through holes) are not transmission linesbut wirings. In order to realize the efficient propagation of powerthrough the transmission line, wiring widths, the thickness of eachinterlayer insulating film, spaces between adjacent patterns, materialphysical values, etc. are designed as parameters so that itscharacteristic impedance becomes a desired value. However, since it isdifficult to make the pattern of each via and each interlayer conductorvertical and constitute them as a coaxial structure, the design forobtaining the desired characteristic impedance is difficult.Accordingly, a loss in power at each via portion is apt to occur.

From this point of view, the technology described in Unexamined PatentPublication No. Hei 5(1993)-167258, for connecting the neighborhood of aportion where a core line of a coaxial cable and its corresponding eachbump pad are connected, as the via configuration will cause acharacteristic impedance mismatch at the connecting portion. Further,the technology is considered to need, when an attempt is made to embedthe coaxial cable into a substrate in its thickness direction, such amanufacturing process that a hole is defined in the substrate by a drillor the like, the coaxial cable is inserted into the hole and thenpositioned therein, and each bump pad and its corresponding core lineare connected to each other, after which the hole is buried. Thisstructure increases the number of processes as compared with a generalprocess of manufacturing a wiring board. This structure will lead tocost up with a difficult technology of cable connection and embedding.

On the other hand, since the wiring board can be manufactured by theknown technology in the first embodiment, no cost up takes place.

Incidentally, the surface layer wirings such as the signal surface layerwiring 4 c, the GND surface layer wirings 4 h employed in the firstembodiment are of wirings which are formed of, for example, copper orthe like and disposed on the uppermost layer on the main surface 4 aside of the package substrate 4. They may be exposed onto the mainsurface 4 a or coated with a non-conductive thin film or the like.

It is desirable that when high-speed transmission such as 40 Gbps or thelike is performed, the signal surface layer wiring 4 c of the microstripline 4 g is of the shortest. Thus, the solder bump electrodes 5, of theplurality of solder bump electrodes 5 connected to the semiconductorchip 2 of the package substrate 4, which are disposed toward the coaxialcable 7 (coaxial connector 11) from the center of the semiconductor chip2, are connected to the signal surface layer wiring 4 c.

Preferably, any of the solder bump electrodes 5 disposed on theoutermost periphery, of the plurality of solder bump electrodes 5 isconnected to the signal surface layer wiring 4 c.

Consequently, high-speed signal transmission in which a loss in thefrequency characteristic of a high frequency has been suppressed to theminimum, can be realized. Since it is possible to reduce carrying ofnoise on the microstrip line 4 g, a reduction in high-frequencycharacteristic can be also suppressed.

In the high-frequency package 1, the plurality of ball electrodes (bumpelectrodes) 3 provided as the external connecting terminals are disposedon the back surface 4 b of the package substrate 4 in an array form.Accordingly, the high-frequency package 1 is a semiconductor package ofa ball grid array type.

Thus, the package can be downsized as compared with an outer-leadprotrusion type high-frequency package wherein outer leads protrudeoutwards from the package substrate 4.

Incidentally, while the microstrip line 4 g transmits a high-frequencysignal as an electromagnetic wave in the insulating layer 4 e lyingbetween the signal surface layer wiring 4 c and its correspondinginternal GND layer 4 f, both of GND surface layer wirings (groundsurface layer wirings) 4 h disposed on both sides of a signal surfacelayer wiring 4 c with an insulating portion interposed therebetween forma microstrip line 4 g in a surface layer of a package substrate 4 asshown in FIG. 7.

A frame member 8 extending along an outer peripheral portion of thepackage substrate 4 is attached to the package substrate 4 in thehigh-frequency package 1. Further, the frame member 8 is provided with acoaxial connector (linkup or junction member) 11 fit onto the coaxialcable 7 together with a glass bead 12. Thus, the coaxial cable 7 is fitin the coaxial connector 11, the core line 7 a of the coaxial cable 7 isconnected to its corresponding core line 12 a of the glass bead 12, andthe core line 12 a is in solder-connection 31 to the signal surfacelayer wiring 4 c of the package substrate 4 (it may be connected theretoby a conductive resin or the like).

Incidentally, the diameter of the coaxial connector 11 is about 10 mm,for example.

The package substrate 4 is a substrate formed of, for example,glass-contained ceramic or the like. The package substrate 4 has athickness of about 1 mm, for example and is formed thereinside with aninternal signal wiring 4 d used as a signal line for connecting theflip-chip connected solder bump electrode 5 and its corresponding ballelectrode 3 used as the external connecting terminal, except for the GNDlayers 4 f.

The high-frequency package 1 having such a structure is built in such anoptical module (semiconductor module device) 14 or the like as shown inFIG. 2 and mounted on its module substrate (junction member) 13.

A structure of the optical module 14 will now be described.

The optical module 14 shown in FIGS. 2 through 5 is a module forhigh-speed optical communications, e.g., a module product mounted to acommunication system apparatus or the like of a communication networkbase station.

The optical module 14 according to the first embodiment has a size of L(ranging from 100 mm to 200 mm)×M (ranging from 60 mm to 150 mm), forexample, as shown in FIG. 2 and a height (T) ranging from 10 mm to 25 mmas shown in FIG. 3. However, the size and height of the optical module14 are not limited to these numerical values.

The high-frequency package 1 according to the first embodiment ismounted on the module substrate 13 of the optical module 14. The modulesubstrate 13 is covered as a whole with a module case 15. A plurality offins 16 are formed side by side on the surface of the module case 15.Placing the fins 16 under wind 18 enables an improvement in thedissipation of the optical module 14.

Incidentally, an external terminal of the optical module 14 is a moduleconnector 17 attached to the module substrate 13. Part of the moduleconnector 17 is exposed to the back side of the module case 15.

In the optical module 14, as shown in FIGS. 4 and 5, a high-frequencylight signal inputted from its input is converted into an electricsignal by an optoelectronic transducer 20. Further, the electric signalpasses through the microstrip line 4 g of the package substrate 4 via anamplifier device 19 so as to enter into the high-frequency semiconductorchip 2 on the input side, followed by transformation into alow-frequency signal, which in turn is transmitted to the outside of theoptical module 14 via the internal signal wiring 4 d of the packagesubstrate 4, the corresponding solder bump electrode 5 and the modulesubstrate 13 shown in FIG. 1 and the module connector 17.

On the other hand, a signal inputted from the module connector 17 passesthrough a path opposite to the above path and is transmitted as anoutput.

Incidentally, while FIG. 4 shows that the high-frequency semiconductorchip 2 is provided two on the input and output sides, the input andoutput sides may be built in one semiconductor chip 2.

In FIG. 4, arrows indicated by solid lines, of arrows indicative of theflows of signals for input and output show the transmission of the lightsignals by optical fibers, whereas arrows indicated by dotted linesthereof show the transmission of the electric signals through thecoaxial cables 7 or microstrip lines 4 g.

Next, FIG. 6 shows a modification of the high-frequency package 1. Acore line 7 a of a coaxial cable 7 is connected directly to a signalsurface layer wiring 4 c of a package substrate 4 by solder or the like.

Namely, the coaxial cable 7 is directly connected to the packagesubstrate 4 without the use of a coaxial connector 11 by solder or thelike.

In this case, a step 4 k for disposing the coaxial cable 7 is providedat an end of the package substrate 4, and a GND surface layer wiring 4 his provided on the surface of the step 4 k. Upon placement of thecoaxial cable 7 on the step 4 k, a shield (GND) 7 b for covering thecore line 7 a of the coaxial cable 7, and the GND surface layer wiring 4h on the step 4 k are electrically connected to each other by solder orthe like.

Owing to the direct attachment of the coaxial cable 7 to the packagesubstrate 4 in this way, the high-frequency package 1 can be reduced inthickness and a cost reduction can be achieved because the coaxialconnector 11 expensive and relatively large in diameter is not used.

A preferable shape or configuration of a GND layer 4 f corresponding toan inner layer in a package substrate 4 will next be explained usingFIGS. 7 through 10.

First, FIGS. 7 and 8 respectively show a case in which the GND layer 4 fplaced inside the substrate extends to an end of the package substrate 4in a microstrip line structure 21 using a microstrip line 4 g, and acase in which a structure wherein a coaxial structure 22 using a coaxialcable 7 and the microstrip line structure 21 are connected to eachother, is taken.

In this case, a high-speed signal inputted from and outputted to thepackage outside passes through a path of the coaxial cable 7, a signalsurface layer wiring 4 c of the package substrate 4 and a semiconductorchip 2. At this time, a core line 7 a of the coaxial cable 7 isconnected to the signal surface layer wiring 4 c of the packagesubstrate 4, and a shield 7 b used as GND, of the coaxial cable 7 isconnected to its corresponding GND surface layer wirings 4 h of thepackage substrate 4.

Further, a frame member 8 for supporting the coaxial cable 7 might befixedly secured onto the package substrate 4. Further, the frame member8 and the shield 7 b of the coaxial cable 7 or the GND surface layerwirings 4 h of the package substrate 4 might be connected to each other.Incidentally, the corresponding GND surface layer wiring 4 h and the GNDlayer 4 f used as the inner layer are connected to each other by viawirings 4 i as shown in FIG. 8.

Thus, in order to bring the signal surface layer wiring 4 c on thepackage 4 to the microstrip line structure 21 over it whole area so asto reduce L (inductance) of GND, there is a need to expose the GND layer4 f at the end of the substrate to thereby connect it to the shield 7 bof the coaxial cable 7 or GND of the frame member 8, or form at thesubstrate end, the via wirings 4 i for connecting the corresponding GNDsurface layer wiring 4 h and the GND layer 4 f used as the inner layerand cut and expose the via wirings 4 i upon substrate cutting-off tothereby connect the same to the coaxial cable 7 or GND of the framemember 8.

However, these technologies need high accuracy upon positioning of thesurface-layer/inner-layer wirings of the package substrate 4 and has afear that when a pasty material such as Cu is used for wiring, it leadsto wiring sagging, and a difficulty arises upon manufacture thereof.

On the other hand, a structure shown in FIGS. 9 and 10 is one formedwith a coplanar line 23 a wherein a signal surface layer wiring 4 c andGND surface layer wirings 4 h are disposed on the same plane (mainsurface 4 a) in an area between the outermost peripheral via wiring 4 iof a plurality of via wirings 4 i and a coaxial cable 7. The coaxialcable 7 and a microstrip line 4 g of a package substrate 4 are connectedto each other through the coplanar line 23 a.

Namely, an area provided outside from the outermost peripheral viawiring 4 i close to the end of the package substrate 4 is defined as acoplanar structure 23. A coaxial structure 22, the coplanar structure 23and a microstrip line structure 21 are connected to one another.

Thus, the inductance of GND can be reduced.

Further, in order to make characteristic impedance matching in an areafor the coplanar structure 23, the distance between the signal surfacelayer wiring 4 c and each of the GND surface layer wirings 4 h isdecreased so that they are brought close to each other as shown in FIG.9. Incidentally, the accuracy of position displacement between the viawiring 4 i and its corresponding GND layer 4 f used as an inner layer isequivalent to the prior art (e.g., about 50 μm). Since a noveltechnology is not required, cost up can be prevented.

Thus, the interconnection of the coaxial structure 22, coplanarstructure 23 and microstrip line structure 21 makes it possible toreduce a loss in high-frequency signal and bring the characteristicimpedance of a high-speed signal path close to a target value.

Further, the characteristic impedance can be brought closer to a targetvalue by decreasing the distance between the signal surface layer wiring4 c and each GND surface layer wiring 4 h in the surface layer of thepackage substrate 4.

As a result, degradation of high-speed signal characteristics can besuppressed and an improvement in the electric characteristics of thehigh-frequency package 1 can be realized without an increase in cost.

A high-frequency package 1 showing a modification illustrated in FIG. 11will next be described.

The high-frequency package 1 shown in FIG. 11 makes use of a thin-typecoaxial connector 24 of a plate-shaped member as a junction memberbetween a coaxial cable 7 and a microstrip line 4 g of a packagesubstrate 4.

The thin-type coaxial connector 24 has a microstrip line 24 c made up ofa signal surface layer wiring (surface layer wiring) 24 a and GND lines(ground wirings) 24 b formed on both sides thereof with insulatingportions interposed therebetween. Thus, in the high-frequency package 1,the signal surface layer wiring 24 a of the microstrip line 4 g of thepackage substrate 4, and a core line 7 a of the coaxial cable 7 areelectrically connected to each other through the signal surface layerwiring 24 a of the microstrip line 24 c of the thin-type coaxialconnector 24.

Namely, the signal surface layer wiring 24 a is provided on the surfaceof an upper stage of a thin ceramic plate or the like with a step 24 d,and the GND lines 24 b are provided on both sides thereof. Further, onlythe GND lines 24 b are provided at a lower stage of the ceramic plate.The GND lines 24 b provided at the upper and lower stages are connectedto each other by means of surface or internal layer vias or the like.

The coaxial cable 7 is then mounted on the lower stage, the core line 7a at a leading end thereof is placed on the signal surface layer wiring24 a at the upper stage, and a shield 7 b of the coaxial cable 7 and theGND lines 24 b at the upper and lower stages of the ceramic plate areconnected to one another by solder or the like. Further, the core line 7a of the coaxial cable 7 and the signal surface layer wiring 24 a at theupper stage are similarly connected to each other by solder or the like.

Thereafter, the surface layer wirings of the ceramic plate are madeopposite to their corresponding surface layer wirings of the packagesubstrate 4, and their mutual wirings are connected to one another bysolder or a conductive resin or the like. Alternatively, they may beconnected by gold (Au)-to-gold (Au) crimping, or the ceramic plate andthe package substrate 4 may be adhered and fixed to each other.

Using the thin-type coaxial connector 24 corresponding to the plate-likemember as the junction member in this way enables a reduction in thethickness of the high-frequency package 1.

Further, the coaxial cable 7 is easy to handle and connector repair isenabled. The thin-type coaxial connector 24 may be attached to both endsof the coaxial cable 7. One end thereof may be formed as the thin-typecoaxial connector 24, whereas the other end thereof may be formed assuch a coaxial connector 11 as shown in FIG. 1. A connector different inshape from the coaxial cable 7 may be attached. Alternatively, one endmay be formed as the thin-type coaxial connector 24, and the other endmay be exposed as a cable end.

Incidentally, only the coaxial cable 7 may be provided as an alternativeto the coaxial cable 7 with the thin-type coaxial connector 24 attachedthereto. Alternatively, the high-frequency package 1 may be provided asthe high-frequency package 1 with such a thin-type coaxial connector 24as shown in FIG. 11 mounted thereto.

A high-frequency package 1 illustrative of a modification shown in FIG.12 will next be described.

Of a plurality of ball electrodes 3 used as external connectingterminals, support balls 3 a are first provided at theoutermost-peripheral four corners as shown in FIG. 15 in thehigh-frequency package 1 shown in FIG. 12.

This is done to cope with such a problem that when the high-frequencypackage 1 is mounted on a mounting board such as a module substrate 13or the like, the ball electrodes 3 are crushed due to the heavy weightof a coaxial connector 11, so that electrical shorts occur between theadjacent ball electrodes 3. Since the support balls 3 a are provided atthe outermost-peripheral four corners, the support balls 3 a at thecorners are capable of supporting a package substrate 4 upon melting ofthe ball electrodes 3 to thereby prevent the occurrence of suchelectrical shorts due to the crushing of the ball electrodes 3.

Incidentally, the support balls 3 a are respectively formed of, forexample, high melting-point solder, a resin or ceramic or the like.

The high-frequency package 1 shown in FIG. 12 has a cap 9 correspondingto a radiating member mounted to a back surface 2 b opposite to a mainsurface 2 a of a semiconductor chip 2 with a thermal conductive adhesive10 interposed therebetween.

Namely, since the high-frequency semiconductor chip 2 might generatehigh heat when driven, the radiating cap 9, or a thermal diffusion plateor radiating fins or the like are attached to the back surface 2 b ofthe semiconductor chip 2, whereby the semiconductor chip 2 can beimproved in dissipation and the high-frequency package 1 can be alsoenhanced in dissipation, thus making it possible to prevent degradationof electric characteristics.

The position of layout of the cap 9 with respect to the packagesubstrate 4 will now be explained. As shown in FIGS. 12 through 14, thecap 9 is mounted onto the back surface 2 b of the semiconductor chip 2with the thermal conductive adhesive 10 or the like interposedtherebetween so as to cover the semiconductor chip 2. At this time, thecap 9 may preferably be disposed even on surface layers (microstrip line4 g) such as a signal surface layer wiring 4 c and GND surface layerwirings 4 h or the like as shown in FIGS. 16 and 20.

Namely, the cap 9 may preferably cover the microstrip line 4 g fromthereabove to avoid carrying of noise on the microstrip line 4 g of thesurface layer due to an external electromagnetic wave.

Accordingly, the cap 9 may preferably cover the semiconductor chip 2 andthe surface layer wirings to some extent to block entrance of theexternal electromagnetic waves. However, the cap 9 and the surface layerwirings such as the signal surface layer wiring 4 c and the GND surfacelayer wirings 4 h or the like must be insulated.

Thus, the package substrate 4 employed in the first embodiment is formedwith openings (wall escape portions) 9 a at leg portions 9 b on asurface layer wiring of a cap 9 as shown in FIG. 17. Each of theopenings takes such a cap shape as not to make contact between the legportions 9 b of the cap 9 and the surface layer wiring.

Incidentally, FIGS. 20 and 22 show in detail the relationship ofposition between the openings 9 a at the leg portions 9 b of the cap 9and the signal surface layer wiring 4 c and GND surface layer wirings 4h of the package substrate 4. Namely, the legs 9 b of the cap 9 areopened as the openings 9 a up to spots lying outside both sides of theGND surface layer wirings 4 h so as not to contact the signal surfacelayer wiring 4 c and the GND surface layer wirings 4 h.

Further, spots other than an area for connection of the signal surfacelayer wiring 4 c corresponding to the surface layer wiring of thepackage substrate 4 to the coaxial cable 7 are covered with a solderresist 4 j corresponding to an insulative thin film (non-conductive thinfilm) formed of a resin or the like as shown in FIG. 20 (GND surfacelayer wirings 4 h are also similar). The solder resist 4 j has aninsulating function and even the function of stopping the flow of solderfor solder connection 31 of the coaxial cable 7.

Thus, since the openings 9 a corresponding to the wall escape portionsof the cap 9, and the solder resist 4 j used as the insulative thin filmare formed with respect to the surface layer wirings, the surface layerwirings and the cap 9 can be prevented from contacting.

Incidentally, the cap 9 is formed, even at the corners and side portionsthereof, with cut-away portions 9 c corresponding to such wall escapeportions as not to contact the surface layer wiring as shown in FIGS. 17and 18.

Since the cap 9 also needs a shield effect, the whole surface of a basematerial 9 d made up of a copper alloy or the like is covered with achrome conductive film 9 e as shown in FIG. 19. Further, only its outersurface is covered with a non-conductive film 9 f so as to preventelectrical shorts developed in other parts.

Such a cap 9 is mounted to the same layer as a signal surface layerwiring 4 c and GND surface layer wirings 4 h formed on a main surface 4a of a package substrate 4 as shown in FIGS. 21 and 22. Incidentally,the cap 9 corresponds to the same layer as a layer for underlyingelectrodes of solder bump electrodes 5.

At spots unformed with an opening 9 a lying between leg portions 9 b ofthe cap 9, the leg portions 9 b are connected to an internal powersupply (or GND layer 4 f) of the package substrate 4 via a conductivematerial 25 and a via wiring 4 i to enhance the shield effect as shownin FIG. 21. The cap 9 per se is electrically connected to internal powersupply layers (or GND layer 4 f and GND surface layer wirings 4 h) ofthe package substrate 4.

Thus, the periphery of each solder bump electrode 5 for a high-frequencysignal is brought to a state of being surrounded by a GND potential, sothat the cap 9-based shield effect can be enhanced.

The solder bump electrode 5 for the high-frequency signal, i.e., thesolder bump electrode 5 connected to the signal surface layer wiring 4 cmay preferably be set as the solder bump electrode 5 disposedapproximately in the center of the side of a row of theoutermost-peripheral solder bump electrodes 5 as shown in FIG. 22. Acoaxial connector 11 connected to the present solder bump electrode 5via the signal surface layer wiring 4 c may also be preferably disposedsubstantially in the center of the side.

Thus, a microstrip line 4 g can be set to the shortest. High-speedsignal transmission can be realized which minimizes a loss in thefrequency characteristic of a high frequency. It is also possible toreduce carrying of noise on the microstrip line 4 g.

Next, a high-frequency package 1 illustrative of a modification shown inFIG. 23 is one having a structure wherein a cap 9 is mounted to thehigh-frequency package 1 using the thin-type coaxial connector 24 shownin FIG. 11. According to the high-frequency package 1 shown in FIG. 23,both thinning and dissipation of the high-frequency package 1 can beenhanced.

A high-frequency package 1 illustrative of a modification shown in FIG.24 is one wherein a radiating block (radiating member) 26 is furthermounted on the surface of a cap 9 attached to a back surface 2 b of asemiconductor chip 2 with a thermal conductive adhesive 10 interposedtherebetween. The high-frequency package 1 can be further enhanced indissipation.

A high-frequency package 1 illustrative of a modification shown in FIG.25 is one showing a structure wherein a second semiconductor chip 27 isfurther mounted on a package substrate 4 in addition to a semiconductorchip 2. A cap 9 for covering both chips is mounted thereon.

In the present example, a signal is inputted via an internal signalwiring 4 d of the package substrate 4 from the semiconductor chip 2connected to a coaxial cable 7 through a microstrip line 4 g in asurface layer to the second semiconductor chip 27. Further, the signalis transmitted from a solder bump electrode 5 of the secondsemiconductor chip 27 to its corresponding ball electrode 3 used as anexternal connecting terminal via an internal signal wiring 4 d.

Both high-frequency packages 1 illustrative of modifications shown inFIGS. 26 and 27 are ones wherein balancers 28 are attached to framemembers 8, respectively. The balancer 28 has the function of adjustingthe center of gravity of the high-frequency package 1 so that thehigh-frequency package 1 is not inclined upon mounting of thehigh-frequency package 1 on a substrate.

FIG. 26 shows the modification wherein the balancer 28 is fixed to theframe member 8 through a screw member 29. FIG. 27 shows the modificationhaving a structure wherein a groove is defined in the balancer 28 andfit onto the frame member 8 to mount the balancer 28 on the frame member8.

Thus, in the high-frequency packages 1 shown in FIGS. 26 and 27, thecenter of gravity of each high-frequency package is adjusted by thebalancer 28 so that the high-frequency package 1 is not inclined uponits mounting onto the substrate.

The positions of placement of the package substrate 4 and thesemiconductor chip 2 will next be described.

In the high-frequency package 1, the semiconductor chip 2 may preferablybe disposed on the package substrate, preferably, in an area close tothe coaxial cable 7.

Namely, when the high-frequency signal is transmitted from the coaxialcable 7 to the semiconductor chip 2 through the microstrip line 4 g inthe surface layer of the package substrate 4, noise is carried on themicrostrip line 4 g when the microstrip line 4 g is long, so thathigh-frequency characteristics are degraded. Therefore, thesemiconductor chip 2 may preferably be disposed so as to lean toward thecoaxial cable 7 as viewed from the central portion of the packagesubstrate 4 in order to prevent it. The semiconductor chip 2 is disposedas close to the coaxial cable 7 as possible.

Thus, the length of the microstrip line 4 g can be shortened and hencethe degradation in the high-frequency characteristics due to thecarrying-on of noise can be suppressed.

The high-frequency package 1 shown in FIG. 13 is one wherein onesemiconductor chip 2 is mounted on a package substrate 4. Thesemiconductor chip 2 is disposed toward a coaxial connector 11 as viewedfrom a central portion of the package substrate 4. By fitting a coaxialcable 7 in the coaxial connector 11, the semiconductor chip 2 isdisposed toward the coaxial cable 7 from the central portion.

FIGS. 28 and 29 respectively show a case in which a high-frequencysemiconductor chip 2 and a low-frequency second semiconductor chip 27are mounted on a package substrate 4. The high-frequency semiconductorchip 2 is disposed toward a coaxial connector 11 as viewed from acentral portion of the package substrate 4 and placed toward the coaxialconnector 11 as viewed from the low-frequency second semiconductor chip27. Further, the two coaxial connectors 11 are attached to onesemiconductor chip 2 in association with each other.

FIG. 30 is a modification of the structure of FIG. 28, wherein acombination of layouts of two coaxial connectors 11 is changed.

FIGS. 31 and 32 respectively show cases in which one semiconductor chips2 are mounted on package substrates 4. FIG. 31 shows the case in whichtwo coaxial connectors 11 are provided at the same side. Thesemiconductor chip 2 is disposed toward the coaxial connectors 11 asviewed from a central portion of the package substrate 4.

Even in the case of FIG. 32, the semiconductor chip 2 is disposed towardcoaxial connectors 11 as viewed from a central portion of the packagesubstrate 4. However, the semiconductor chip 2 is disposed symmetricallyface to face with two sides to which the two coaxial connectors 11 areopposed.

In a high-frequency package 1 shown in FIGS. 33 and 34, onesemiconductor chip 2 is disposed toward a coaxial connector 11 as viewedfrom a central portion, and the coaxial connector 11 is provided at theside closest to the semiconductor chip 2 in association with thesemiconductor chip 2. Further, a plurality of chip condensers 30 aremounted on the periphery of the semiconductor chip 2 on a main surface 4a of a package substrate 4 a.

Namely, since the semiconductor chip 2 is disposed toward the coaxialconnector 11 as viewed from the central portion, the plurality of chipcondensers 30 or the like can be mounted in vacant spaces on theopposite sides beside the semiconductor chip 2.

On the other hand, a high-frequency package 1 shown in FIGS. 35 and 36takes a configuration wherein one semiconductor chip 2 is disposedtoward a coaxial connector 11 from a central portion, and a plurality ofchip condensers 30 are placed in a chip-adaptable area of a back surface4 b of a package substrate 4. In a high-frequency package 1 shown inFIGS. 37 and 38, one semiconductor chip 2 is disposed toward a coaxialconnector 11 from a central portion, and a plurality of chip condensers30 are mounted in a concave portion 41 corresponding to a cavity definedin a chip-compatible area of a back surface 4 b of a package substrate4.

Even in the case of any high-frequency packages 1 shown in FIGS. 28through 38, their size reductions, their thinning and their costreductions can be achieved.

(Second Embodiment)

FIG. 39 is a cross-sectional view showing a structure of a semiconductordevice (high-frequency package) according to a second embodiment of thepresent invention, FIGS. 40 and 41 are respectively cross-sectionalviews showing structures of high-frequency packages illustrative ofmodifications of the second embodiment of the present invention, FIG. 42is a cross-sectional view showing one example of a state in which a capis mounted upon assembly of the high-frequency package shown in FIG. 41,FIG. 43 is a partly cross-sectional view depicting one example of astate in which an auxiliary substrate and a coaxial cable are connectedto each other upon assembly of the high-frequency package shown in FIG.41, FIG. 44 is a partly cross-sectional view showing one example of atesting state at the assembly of the high-frequency package shown inFIG. 41, and FIG. 45 is a partly cross-sectional view depicting oneexample of a structure subsequent to the completion of assembly of thehigh-frequency package shown in FIG. 41, respectively.

While the semiconductor device shown in FIG. 39 according to the secondembodiment is a high-frequency semiconductor package for opticalcommunications, having a coaxial cable 7 in a manner similar to thehigh-frequency package 1 according to the first embodiment, such acoaxial cable 7 as described in the first embodiment is not mounted viathe coaxial connector 11 or the coaxial cable 7 is not mounted to thepackage substrate 4 corresponding to the chip carrier by directconnection. The present semiconductor device is one having a structurewherein the coaxial cable 7 is connected to the module substrate 13 ofthe optical module 14 (semiconductor module device) shown in FIG. 2, andthe module substrate 13 is connected to the package substrate 4 viaprotruded electrodes.

Thus, the module substrate 13 is used as a junction member at thetransmission of a high-frequency signal from the coaxial cable 7 to thepackage substrate 4. The module substrate 13 is also formed, at asurface layer of its main surface 13 a, with a microstrip line 13 g madeup of a signal surface layer wiring (surface layer wiring) 13 c and aGND layer (ground conductor layer) 13 f formed inside via the signalsurface layer wiring 13 c and an insulating layer 13 e.

Now, a signal surface layer wiring 4 c of a microstrip line 4 g of apackage substrate 4, and a core line 7 a of the coaxial cable 7 areconnected to each other through the signal surface layer wiring 13 c ofthe microstrip line 13 g of the module substrate 13.

Namely, since thin-type ball electrodes 34 used as external connectingterminals are formed on a main surface 4 a on the flip-chip connectionside, of the package substrate 4, the main surface 4 a of the packagesubstrate 4 and its corresponding main surface 13 a of the modulesubstrate 13 are disposed in an opposing relationship. Consequently, thesignal surface layer wiring 4 c of the package substrate 4, and thesignal surface layer wiring 13 c of the module substrate 13 can beconnected to each other via the thin-type ball electrodes 34 made up ofsolder or the like. Thus, the microstrip line 4 g of the packagesubstrate 4 and the microstrip line 13 g of the module substrate 13 areconnected to each other via the thin-type ball electrodes 34.

Accordingly, the high-frequency package 1 according to the secondembodiment is also capable of directly introducing a signal of a highfrequency (e.g., 40 Gbps) sent from the coaxial cable 7 into thecorresponding semiconductor chip 2 via the signal surface layer wiring13 c of the module substrate 13 and the thin-type ball electrodes 34.The high-frequency signal can be transmitted by only the microstrip lineat the whole surface layer of the package substrate 4 via the modulesubstrate 13.

Consequently, the high-frequency signal is transmitted by only themicrostrip lines at the surface layers of the module substrate 13 andthe package substrate 4 without through via-based wirings or the like ina manner similar to the high-frequency package 1 according to the firstembodiment, thereby making it possible to transmit the high-frequencysignal without causing a loss in frequency characteristic.

Incidentally, a signal on the low frequency side passes through aninternal signal wiring 4 d of the package substrate 4 and then passesthrough an internal signal wiring 13 d of the module substrate 13 viathe corresponding thin-type ball electrode 34, followed by transmissionto the outside.

The semiconductor chip 2 is disposed in an opening 13 h of the modulesubstrate 13 in a state of being flip-chip connected to the packagesubstrate 4. Further, a radiating block (radiating member) 26 isattached to a back surface 2 b of the semiconductor chip 2 with athermal conductive adhesive 10 interposed therebetween. Accordingly, theradiating block 26 is disposed on the back surface 13 b side of themodule substrate 13.

Since the high-frequency package 1 according to the second embodimenthas a structure wherein the module substrate 13 is interposed betweenthe coaxial cable 7 and the package substrate 4 without directlyconnecting the coaxial cable 7 to the package substrate 4, an IC makeris capable of handling as a product, a structural body wherein thesemiconductor chip 2 is flip-chip connected to the package substrate 4.

In this case, the coaxial cable 7 is connected to the module substrate13 on the user side. Further, the user connects the package substrate 4and the module substrate 13 via the thin-type ball electrodes 34 tothereby assemble the high-frequency package 1.

In the high-frequency package 1 using the module substrate 13 as thejunction member in this way, the package substrate 4 equipped with thesemiconductor chip 2 and the module substrate 13 connected with thecoaxial cable 7 are assembled in a discrete form and thereafter both areconnected to each other. It is therefore possible to divide theiryields.

Namely, an assembled body of the semiconductor chip 2 and an assembledbody of the coaxial cable 7 can share yield risks respectively, and theyields of a structural body subsequent to the connection of bothassembled bodies can be enhanced.

Since the high-frequency package 1 using the module substrate 13 doesnot use the expensive coaxial connector 11, it can be reduced in costand thinned.

Further, since all the external connecting terminals are provided on themain surface 4 a on the flip-chip connection side, of the packagesubstrate 4, a screening test can be easily performed upon screening ofsemiconductor chips 2 each used for the high frequency of 40 Gbps.

Namely, since all the external connecting terminals for the high and lowfrequencies are provided on one-sided surface (main surface 4 a) of thepackage substrate 4, a probe becomes easy to contact upon the screeningtest. The test can be performed without using a jig having a complexshape.

As a result, a test time interval can be shortened.

Incidentally, a high-frequency package 1 illustrative of a modificationshown in FIG. 40 is one wherein a cap 9 is mounted onto a back surface 2b of a semiconductor chip 2 with a thermal conductive adhesive 10interposed therebetween. Further, a radiating block 26 is mounted on thesurface of the cap 9 with a thermal conductive adhesive 10 interposedtherebetween.

In this case, the cap 9 is formed with an opening (wall escape portion)9 a for isolating the cap 9 and surface layer wirings such as a signalsurface layer wiring 4 c, etc. from one another.

Further, since the radiating block 26 is provided on the cap 9 as wellas the cap 9, the high-frequency package 1 shown in FIG. 40 is capableof further enhancing dissipation or radiation thereof and preventingdegradation of high-frequency characteristics.

Next, a high-frequency package 1 illustrative of a modification shown inFIG. 41 has a configuration wherein a junction member for connecting acoaxial cable 7 and a signal surface layer wiring 4 c of a packagesubstrate 4 is of a sub or auxiliary substrate 32 corresponding to asecond package substrate. The auxiliary substrate 32 is formed, at asurface layer of its main surface 32 a, with a microstrip line 32 g madeup of a signal surface layer wiring (surface layer wiring) 32 c and aGND layer (ground conductor layer) 32 f formed inside via the signalsurface layer wiring 32 c and an insulating layer 32 e.

Now, the signal surface layer wiring 4 c for a microstrip line 4 g ofthe package substrate 4, and a core line 7 a of the coaxial cable 7 areconnected to each other through the signal surface layer wiring 32 c ofthe microstrip line 32 g of the auxiliary substrate 32.

Namely, since thin-type ball electrodes 34 used as external connectingterminals are formed on a main surface 4 a on the flip-chip connectionside, of the package substrate 4, the main surface 4 a of the packagesubstrate 4 and its corresponding main surface 32 a of the auxiliarysubstrate 32 are disposed in an opposing relationship. Consequently, thesignal surface layer wiring 4 c of the package substrate 4, and thesignal surface layer wiring 32 c of the auxiliary substrate 32 can beconnected to each other via the thin-type ball electrodes 34 made up ofsolder or the like. Thus, the microstrip line 4 g of the packagesubstrate 4 and the microstrip line 32 g of the auxiliary substrate 32are connected to each other via the thin-type ball electrodes 34.

Accordingly, the high-frequency package 1 according to the modificationshown in FIG. 41 is also capable of directly introducing a signal of ahigh frequency (e.g., 40 Gbps) sent from the coaxial cable 7 into thecorresponding semiconductor chip 2 via the signal surface layer wiring32 c of the auxiliary substrate 32 and the thin-type ball electrodes 34.The high-frequency signal can be transmitted by only the microstrip lineat the whole surface layer of the package substrate 4 via the auxiliarysubstrate 32.

Consequently, the high-frequency signal is transmitted by only themicrostrip lines at the surface layers of the auxiliary substrate 32 andthe package substrate 4 without through via-based wirings or the like ina manner similar to the high-frequency package 1 according to the firstembodiment, whereby the high-frequency signal can be transmitted withoutcausing a loss in frequency characteristic.

Incidentally, a signal on the low frequency side passes through aninternal signal wiring 4 d of the package substrate 4 and then passesthrough an internal signal wiring 32 d of the auxiliary substrate 32 viathe corresponding thin-type ball electrode 34. Further, the signal istransmitted to a module substrate 13 or the like via a pin member(connecting terminal) 33.

The semiconductor chip 2 is disposed in an opening 32 h of the auxiliarysubstrate 32 in a state of being flip-chip connected to the packagesubstrate 4. Further, a cap 9 is attached to a back surface 2 b of thesemiconductor chip 2 with a thermal conductive adhesive 10 interposedtherebetween. Furthermore, a radiating block (radiating member) 26 ismounted on the surface of the cap 9. Accordingly, the radiating block 26is disposed on the back surface 32 b side of the auxiliary substrate 32.

The high-frequency package 1 according to the second embodiment isdivided into parts on the coaxial cable 7 side and parts on thesemiconductor chip 2 side and respectively sorted, and the non-defectiveparts are connected to one another, whereby the yield of thehigh-frequency package 1 can be improved.

Namely, a chip-side structural body 36 shown in FIG. 42 wherein asemiconductor chip 2 with a cap 9 mounted thereon is flip-chipconnected, and a cable-side structural body 37 shown in FIG. 43 whereina coaxial cable 7 is connected to an auxiliary substrate 32 by solderconnection 31, are respectively assembled. The respective structuralbodies are selected and tested separately.

Thus, since both the structural bodies include microstrip lines, ahigh-frequency test can be effected on their parts, and thenon-defective parts are connected to one another, so that their yieldscan be divided. As a result, the chip-side structural body 36 and thecable-side structural body 37 can share yield risks respectively, andthe yield of the high-frequency package 1 shown in FIG. 41 to which bothstructural bodies are connected, can be improved.

Further, the chip-side structural body 36 and the cable-side structuralbody 37 can be respectively put in circulation as singular parts, andthey are available as parts.

Since all the external connecting terminals are provided on the mainsurface 4 a on the flip-chip connection side, of the package substrate4, a screening test can be easily performed upon screening ofsemiconductor chips 2 each used for the high frequency of 40 Gbps.

Namely, since all the external connecting terminals for the high and lowfrequencies are provided on one-sided surface (main surface 4 a) of thepackage substrate 4, a probe becomes easy to contact upon the screeningtest. The test can be performed without using a jig having a complexshape.

As a result, a test time interval can be shortened.

Incidentally, the auxiliary substrate 32 may be used as a testingsubstrate 35 as shown in FIG. 44. Alternatively, it may be used as asocket upon a screening test of each package substrate 4.

At this time, the package substrate 4 and the testing substrate 35 areelectrically brought into contact with each other with an interposer 35a such as an ACF (Anisotropic Conductive Film) or the like. A signal istransmitted to the outside through a corresponding pin member 35 b tothereby test the package substrate 4.

Incidentally, the testing substrate 35 is formed with a signal surfacelayer wiring 35 c, an internal signal wiring 35 d, GND layers 35 fdisposed through the signal surface layer wiring 35 c and an insulatinglayer 35 e, and a microstrip line 35 g in a manner similar to theauxiliary substrate 32.

The chip-side structural body 36 shown in FIG. 42 and the cable-sidestructural body 37 shown in FIG. 43 are respectively selected and testedin several. Non-defective products are obtained for them. Thereafter,the chip-side structural body 36 and the cable-side structural body 37are connected and assembled. The resultant one is a high-frequencypackage 1 illustrative of a modification of the second embodiment shownin FIG. 45.

Further, one wherein a thermal conductive adhesive 10 is applied ontothe surface of a cap 9, a radiating block 26 is mounted thereon with thethermal conductive adhesive 10 interposed therebetween, and thehigh-frequency package 1 is mounted on its corresponding modulesubstrate 13 of an optical module 14 through pin members 35 b, is amounting structure shown in FIG. 41.

Incidentally, the cap 9 is first mounted onto its corresponding backsurface 2 b of the semiconductor chip 2 with the thermal conductiveadhesive 10 interposed therebetween, and the radiating block 26 ismounted on the surface of the cap 9 with the thermal conductive adhesive10 interposed therebetween in the high-frequency package 1 shown in FIG.41. In the optical module 14, however, a module case 15 shares the roleof the radiating block 26. Further, the cap 9 is formed with an opening(wall escape portion) 9 a for isolating the cap 9 and the surfacewirings such as the signal surface layer wiring 4 c or the like from oneanother.

Thus, since the radiating block 26 (module case 15) is provided on thecap 9 as well as the cap 9, the high-frequency package 1 shown in FIG.41 is also capable of further enhancing dissipation or radiation thereofand preventing degradation of high-frequency characteristics.

(Third Embodiment)

FIG. 46 is a plan view showing one example of a layout of parts built inan optical module according to a third embodiment of the presentinvention, FIG. 47 is a cross-sectional view illustrating one example ofthe layout of the parts built in the optical module shown in FIG. 46,FIG. 48 is a cross-sectional view showing a modification of a connectingmethod of a transmission line section employed in the optical moduleshown in FIG. 46, FIG. 49 is a plan view depicting a layout of partsbuilt in an optical module illustrative of a modification of the thirdembodiment of the present invention, FIG. 50 is a cross-sectional viewshowing one example of the layout of the parts built in the opticalmodule shown in FIG. 49, FIG. 51 is a plan view illustrating a structureof a tape-shaped transmission line section showing one example of thetransmission line section employed in the third embodiment of thepresent invention, FIG. 52 is a cross-sectional view showing a structureof a cross-section cut along line A—A shown in FIG. 51, FIG. 53 is across-sectional view illustrating a structure of a cross-section cutalong line B—B shown in FIG. 51, FIG. 54 is a back view showing astructure of a back surface of the tape-shaped transmission line sectionshown in FIG. 51, FIG. 55 is a cross-sectional view illustrating astructure of a cross-section cut along line C—C shown in FIG. 51, FIG.56 is a plan view showing a structure of a tape-shaped transmission linesection illustrative of a modification of the third embodiment of thepresent invention, FIG. 57 is a cross-sectional view illustrating astructure of a cross-section cut along line A—A shown in FIG. 56, FIG.58 is a cross-sectional view showing a structure of a cross-section cutalong line B—B shown in FIG. 56, FIG. 59 is a back view depicting astructure of a back surface of the tape-shaped transmission line sectionshown in FIG. 56, FIG. 60 is a cross-sectional view illustrating astructure of a cross-section cut along line C—C shown in FIG. 56, FIG.61 is a plan view showing a structure of a tape-shaped transmission linesection illustrative of another modification of the third embodiment ofthe present invention, FIG. 62 is a cross-sectional view depicting astructure of a cross-section cut along line A—A shown in FIG. 61, FIG.63 is a cross-sectional view showing a structure of a cross-section cutalong line B—B shown in FIG. 61, FIG. 64 is a back view showing astructure of a back surface of the tape-shaped transmission line sectionshown in FIG. 61, FIG. 65 is a cross-sectional view illustrating astructure of a cross-section cut along line C—C shown in FIG. 61, FIG.66 is a cross-sectional view showing one example of a mounting structureof a high-frequency package provided with the tape-shaped transmissionline section according to the third embodiment of the present invention,FIG. 67 is an enlarged partly cross-sectional view showing, in adeveloped form, a structure of a portion D shown in FIG. 66, FIG. 68 isa cross-sectional view illustrating a structure of a cross-section cutalong line E—E shown in FIG. 67, FIG. 69 is a cross-sectional viewshowing a modification of the structure shown in FIG. 68, FIG. 70 is across-sectional view illustrating a modification of the structure shownin FIG. 66, FIG. 71 is a cross-sectional view showing anothermodification of the structure shown in FIG. 66, FIG. 72 is a plan viewshowing a structure of a tape-shaped transmission line sectionillustrative of a further modification of the third embodiment of thepresent invention, FIG. 73 is a plan view showing a connected state ofthe tape-shaped transmission line section illustrative of themodification shown in FIG. 72, FIG. 74 is a cross-sectional view showinga mounting structure of a still further modification of the tape-shapedtransmission line section according to the third embodiment of thepresent invention, and FIG. 75 is a cross-sectional view illustrating amounting structure of a still further modification of the tape-shapedtransmission line section according to the third embodiment of thepresent invention, respectively.

The third embodiment describes high-frequency packages (semiconductordevices) 38 each mounted to a piece of an electronic device such as anoptical module 39 or the like shown in FIG. 46 having a structuresimilar to the optical module 14 described in the first embodiment.

Namely, the high-frequency package 38 is also of a semiconductor packageequipped with an optical communication IC. This is a semiconductordevice capable of performing high-speed transmission at 1 GHz or more,e.g., 40 Gbps. Incidentally, the high-frequency package 38 has atape-shaped line section 40 corresponding to such a tape-liketransmission line section as shown in FIGS. 51 through 55 as atransmission line section for a high-frequency signal. The input oroutput of the high-frequency signal to and from a semiconductor chip 2is performed via the tape-shaped line section 40. Accordingly, thetape-shaped line section 40 is a member which performs the transfer of ahigh-speed, signal.

The high-frequency package 38 comprises a package substrate (wiringboard) 4 formed with such a signal surface layer wiring (surface layerwiring) 4 c as shown in FIG. 66, a high-frequency semiconductor chip 2electrically connected to and mounted onto a main surface 4 a of thepackage substrate 4 by flip-chip connection with a plurality of solderbump electrodes 5 interposed therebetween, a tape-shaped line section 40electrically connected to the signal surface layer wiring 4 c of thepackage substrate 4, an underfill resin 6 poured between a main surface2 a (see FIG. 1) of the semiconductor chip 2 and the main surface 4 a ofthe package substrate 4 to protect the flip-chip connected portion, andball electrodes 3 used as a plurality of external connecting terminalsdisposed within a back surface 4 b located on the side opposite to themain surface 4 a of the package substrate 4.

Further, the tape-shaped line section 40 according to the thirdembodiment has plate-shaped leads 40 a which are transmission lines andhigh-frequency wirings as shown in FIG. 51. The plate-shaped lead 40 ais electrically connected to the signal surface layer wiring 4 c of thepackage substrate 4.

Incidentally, the package substrate 4 is formed with a microstrip line 4g made up of a signal surface layer wiring 4 c and GND layers (groundconductor layers) 4 f formed inside via the signal surface layer wiring4 c and an insulating layer 4 e as shown in FIG. 1.

Accordingly, the high-frequency package 38 according to the thirdembodiment directly inputs a signal of a high frequency (e.g., 40 Gbps)sent from the tape-shaped line section 40 to the semiconductor chip 2through the corresponding solder bump electrode 5 by way of the signalsurface layer wiring 4 c of the package substrate 4 or outputs ahigh-frequency signal sent from the semiconductor chip 2 to the outsidevia the tape-shaped line section 40 in reverse in a manner similar tothe high-frequency package 1 according to the first embodiment. Thehigh-frequency package 38 has a structure wherein the high-frequencysignal can be transmitted by only the microstrip line at the wholesurface layer of the package substrate 4.

As a result, the high-frequency signal can be transmitted without a lossin frequency characteristic owing to the transmission of thehigh-frequency signal by only the microstrip line at the surface layerof the package substrate 4 without through via-based wirings or thelike.

Described specifically, reflective characteristics at high-frequencytransmission can be reduced and penetrative or transmissivecharacteristics can be enhanced owing to the transmission of thehigh-frequency signal by only the microstrip line at the surface layer.Thus, a loss at the high-frequency transmission can be reduced and ahigh-quality high-frequency signal can be transmitted.

It is further possible to reduce disturbance in the waveform of thesignal of the high frequency at the high-frequency transmission.Accordingly, the transmission of a high-quality high-frequency signal isenabled.

Namely, since a characteristic impedance mismatch occurs when vias areprovided upon high-frequency transmission as described in the firstembodiment, it can result in a transmission loss. However, if themicrostrip line is used, then a desired characteristic impedance can beobtained with the design of parameters such as a wiring width, thethickness of an insulating layer, a space between adjacent patterns,etc. Accordingly, the uniform characteristic impedance can be designedbetween the input side and the output side and hence a transmission losscan be reduced.

Incidentally, the surface layer wirings of the package substrate 4, suchas the signal surface layer wiring 4 c, the GND surface layer wiring 4h, etc. are formed of, for example, copper or the like. The surfacelayer wirings correspond to wirings disposed in the top layer on themain surface 4 a side of the package substrate 4, which may be exposedonto the surface of the main surface 4 a. Alternatively, they may becoated with a non-conductive thin film or the like.

In the high-frequency package 38 as well, a plurality of ball electrodes(bump electrodes) 3 provided as external connecting terminals aredisposed on a back surface 4 b of the package substrate 4 in an arrayform in a manner similar to the high-frequency package 1. Accordingly,the high-frequency package 38 is also of a semiconductor package of aball grid array type.

Thus, the package can be brought into less size as compared with anouter-lead protrusion type high-frequency package wherein outer leadsprotrude outwards from a package main body.

The optical module 39 shown in FIG. 46, which is equipped with thehigh-frequency packages 38, will next be explained.

The optical module 39 according to the third embodiment is similar instructure to the optical module 14 according to the first embodiment.The optical module 39 converts an input light signal to an electricsignal by means of an optoelectronic transducer (other semiconductordevice) 20, amplifies the same by means of an amplifier device (othersemiconductor device) 19, and thereafter performs arithmetic processinginside the semiconductor chip according to the electric signal, andfurther converts the result of its processing to a light signal again,followed by output to the following module product.

In the optical module 39 shown in FIG. 46, a signal of a high frequencyon the order of a giga (G) Hz is inputted/outputted to the followingstages of the amplifier devices 19. Accordingly, the high-frequencypackages 38 and the amplifier devices 19 corresponding to othersemiconductor devices are respectively connected via the tape-shapedline sections 40.

A description will now be made to the connections made via thetape-shaped line sections 40. Upon the connection between thehigh-frequency packages 38 and the amplifier devices 19 mounted on thesame module substrate 13, the respective tape-shaped line sections 40are connected to the module substrate 13 once, and the high-frequencypackages 38 and the amplifier devices 19 are respectively electricallyconnected to one another through surface layer wirings on the modulesubstrate 13 and the tape-shaped line sections 40.

As shown in FIG. 48, the high-frequency packages 38 and the amplifierdevices 19 can be directly connected to one another by theircorresponding tape-shaped line sections 40.

Namely, since the tape-shaped line sections 40 have flexibility, theyare shaped in a bent form in advance. It is thus possible to easilypackage the high-frequency packages 38 or the amplifier devices 19.

On the other hand, since the tape-shaped line section 40 hasflexibility, both parts different in height can be directly connected bythe tape-shaped line section 40 even if the parts are used. Accordingly,the distance between both parts can be shortened as shown in FIG. 48,and a packaging area can be reduced. Since the surface layer wirings ofthe module substrate 13 are not interposed between the parts upontransmission of a high-frequency signal between the parts, a loss at thetransmission of the high-frequency signal can be further reduced, andthe quality of transmission of the high-frequency signal can beenhanced.

The optical module 39 shown in FIGS. 49 and 50 has a structure whereintape-shaped line sections 40 are respectively interposed betweenamplifier devices 19 and optoelectronic transducers (other semiconductordevices) 20 as well as between high-frequency packages 38 and theamplifier devices 19. Further, a packaging area of each part can bereduced and the quality of transmission of a high-frequency signal canbe enhanced.

Incidentally, a circuit for dividing, for example, an input signalhaving a first frequency into a plurality of signals each having asecond frequency smaller than the first frequency and outputting thesame is built in the semiconductor chip 2 provided with the tape-shapedline section 40 on the signal input side in the optical module 39 shownin FIG. 46. On the other hand, a circuit for integrating or combining,for example, a plurality of input signals each having a third frequencyinto a signal having a fourth frequency larger than the third frequencyand outputting the same is incorporated into the semiconductor chip 2provided with the tape-shaped line section 40 on the signal output side.The first and fourth frequencies are 1 GHz or more.

Since other structures other than the tape-shaped line sections 40, ofthe structures of the optical modules 39 shown in FIGS. 46 through 50related to the third embodiment are similar to the optical module 14shown in FIG. 4, the description of common ones will be omitted.

A configuration of the tape-shaped line section 40 mounted to thehigh-frequency package 38 according to the third embodiment will next bedescribed.

The tape-shaped line section 40 shown in FIGS. 51 through 55 is such afour-layer structured tape-shaped member as shown in FIG. 52, whichcomprises a single base metal layer (ground conductor layer) 40 b set toa ground potential shown in FIG. 54, an insulating layer 40 c disposedthereon, a surface layer metal layer 40 d formed thereon, and a covercoat layer 40 e corresponding to a solder resist for covering thesurface layer metal layer 40 d.

As shown in FIG. 51, the surface layer metal layer 40 d has a surfacelayer signal lead 40 g corresponding to a plate-shaped lead 40 adisposed along its longitudinal direction in the vicinity of the centerthereof as viewed in its transverse direction, and surface GND leads 40h disposed along the longitudinal direction thereof on both sidesthereof. Further, the base metal layer 40 b and the two surface layerGND leads 40 h are respectively connected to one another by a pluralityof vias 40 f as shown in FIGS. 53 and 55 and brought to the groundpotential corresponding to the same potential.

Namely, the surface layer GND leads 40 h are respectively disposed onboth sides of the surface layer signal lead 40 g of the surface layermetal layer 40 d through the insulative cover coat layer 40 e. Further,the base metal layer 40 b is disposed on the back side of the surfacelayer signal lead 40 g with the insulating layer 40 c interposedtherebetween. Thus, the tape-shaped line section 40 is formed with amicrostrip line 40 i as shown in FIG. 55.

As a result, a high-frequency signal is transmitted to othersemiconductor device such as the amplifier device 19, and the modulesubstrate 13 or the like via the signal surface layer wiring 4 c of thepackage substrate 4 and the surface layer signal lead 40 g of themicrostrip line 40 i of the corresponding tape-shaped line section 40,whereby the loss at high-frequency transmission is reduced andhigh-quality transmission of a high-frequency signal can be performed.

Incidentally, the base metal layer 40 b is formed of stainless steel(SUS) or the like. The thickness thereof ranges from about 0.1 mm toabout 0.2 mm, for example. The surface layer metal layer 40 d is a thinfilm of copper, for example, and the thickness thereof ranges from aboutseveral tens of μm to about 35 μm, for example. The insulating film 40 cis formed of a polyimide resin or the like, for example.

However, the quality and thickness or the like of each of theconstituent members of each tape-shaped line section 40 are not limitedto the above ones.

Incidentally, while the surface layer metal layer 40 d is formed on thesurface of the insulating layer 40 c in the tape-shaped line section 40shown in FIGS. 51 through 55, the surface layer metal layer 40 d isformed of a wiring pattern of copper or the like. Further, the basemetal layer 40 b on the back side of the insulating layer 40 c is oneobtained by lining a metal thin plate having elasticity, for example.

Owing to the placement of the base metal layer 40 b on the back side ofthe insulating layer 40 c, the tape-shaped line section 40 is easy tobend and mold, and its bent shape can be keep uniform. It is thus easyto shape a gull-wing form. As a result, the tape-shaped line sections 40can be disposed with respect to the high-frequency package 38 to themodule substrate 13 or the like or the high-frequency package 38 toother semiconductor device with high accuracy. An improvement inworkability at packaging can be achieved and the packaging property ofthe high-frequency package 38 can be enhanced.

The tape-shaped line section 40 according to the modification shown inFIGS. 56 through 60 includes a metal layer 40 j set to a groundpotential, which is provided over a base metal layer 40 b with anadhesive 40 l interposed therebetween as shown in FIG. 60. The metallayer 40 j is electrically connected to surface layer GND leads 40 h viaa plurality of vias 40 f. Since one layer is increased as the layerformed of copper foil set to the ground potential as compared with thetape-shaped line section 40 shown in FIGS. 51 through 55, a resistancevalue can be reduced as compared with the provision of the base metallayer 40 b alone, and electric characteristics can be enhanced.

However, since the tape-shaped line section 40 shown in FIGS. 51 through55 is simple in structure as compared with the tape-shaped line section40 illustrative of the modification shown in FIGS. 56 through 60, a costreduction can be achieved.

The tape-shaped line section 40 shown in FIGS. 61 through 65 includes asurface layer metal layer 40 d and a metal layer 40 j provided as wiringpatterns. Both are electrically connected to each other by a pluralityof vias 40 f. The surface layer metal layer 40 d and the metal layer 40j are respectively covered with a cover coat layer 40 e corresponding toan insulative solder resist.

In the tape-shaped line section 40 illustrative of the modificationshown in FIGS. 61 through 65, the metal layer 40 j can be also patternedbecause of copper foil. The tape-shaped line section 40 is capable offurther improving electric characteristics as compared with thetape-shaped line section 40 shown in FIGS. 51 through 55. Since thetape-shaped line section 40 is simple in structure as compared with thetape-shaped line section 40 illustrative of the modification shown inFIGS. 56 through 60, the cost thereof can be reduced. Since thetape-shaped line section 40 also has flexibility, parts different inheight can be easily connected to each other.

With the use of such tape-shaped line sections 40 as shown in FIGS. 51through 65 as high-frequency signal transmission line sections, thehigh-frequency package 38 according to the third embodiment can bereduced in size and thinned as compared with the high-frequency package1 using the coaxial cable 7, according to the first embodiment. Sincethe tape-shaped line section 40 is considerably low in cost as comparedwith the coaxial cable 7, the cost of the high-frequency package 38 canbe lowered.

Since the transmission lines such as the surface layer signal lead 40 gand the surface layer GND leads 40 h or the metal layer 40 j formed inthe tape-shaped line section 40 can be formed as the wiring patterns bya photolitho technology, the dimensions of each transmission line can beformed with high accuracy, and the design thereof can be facilitated.

Next, FIGS. 66 through 71 respectively show mounting structures(electronic devices) of high-frequency packages 38, which are oneswherein the high-frequency packages 38 equipped with tape-shaped linesections 40 each formed with being bent in a gull-wing fashion arerespectively packaged over mounting boards 41.

Since the tape-shaped line sections 40 are formed with being bent in thegull-wing fashion, packaging work is easy and packageability can beimproved. When the tape-shaped line sections 40 are formed with beingbent in the gull-wing form in this way, the tape-shaped line sections 40provided with the lined base metal layers 40 b may preferably be used asin the tape-shaped line section 40 shown in FIGS. 51 through 55 and thetape-shaped line section 40 illustrative of the modification shown inFIGS. 56 through 60.

Incidentally, FIGS. 67 and 68 respectively show the details of aconnected state of the tape-shaped line section 40 and the mountingboard 41. A surface layer signal lead (transmission line) 40 g of thetape-shaped line section 40 and a signal surface layer wiring(electrode) 41 a of the mounting board 41, and surface layer GND leads(transmission lines) 40 h of the tape-shaped line section 40 and theircorresponding GND surface layer wirings (electrodes) 41 b of themounting board 41 are respectively connected to one another with solder42 interposed therebetween.

FIG. 69 shows a case in which an anisotropic conductive resin 43 is usedas an alternative to the solder 42. A surface layer signal lead 40 g ofa tape-shaped line section 40 and a signal surface layer wiring 41 a ofa mounting board 41, and surface layer GND leads 40 h of the tape-shapedline section 40 and GND surface layer wirings 41 b of a mounting board41 are respectively electrically connected to one another by conductiveparticles 43 a.

Using the solder 42 and the anisotropic conductive resin 43 in this waymakes it possible to detach the respective tape-shaped line sections 40.Consequently, each high-frequency package 38 can be easily repaired.

When the high-frequency package 38 is packaged as shown in FIG. 70, ballelectrodes 3 used as its external connecting terminals and tape-shapedline sections 40 may be connected to different discrete mounting boards41 without being connected to the same mounting board 41. Namely, sincethe shape of the tape-shaped line section 40 has a degree of freedom,such mounting structures can be realized.

FIG. 71 shows a structure wherein a high-frequency package 38 and othersemiconductor package (other semiconductor device) 44 are electricallyconnected to each other by a tape-shaped line section 40. Since thehigh-frequency package 38 and other semiconductor package 44 are oftendifferent in height in this case, such a tape-shaped line section 40 asindicated by the modification shown in FIGS. 61 through 65, havingrelatively flexibility may preferably be used. Thus, even if thedifference in height occurs between the two, they can be easilyconnected.

Incidentally, the high-frequency package 38 provided with thetape-shaped line section 40 in advance is mounted on its correspondingmounting substrate 41. Thereafter, the tape-shaped line section 40 andother semiconductor package 44 may be connected to each other.Alternatively, the high-frequency package 38 having no tape-shaped linesection 40, and other semiconductor package 44 are packaged on thecorresponding mounting board 41, and thereafter the tape-shaped linesection 40 may be connected to the two. In either case, the tape-shapedline section 40 having relatively ductility (flexibility) may preferablybe used.

Further, since the tape-shaped line section 40 is directly connected tothe high-frequency package 38 and other semiconductor package 44 withoutbeing connected to the mounting board 41 in the mounting structure shownin FIG. 71, the distance between the packages can be shortened, and apackaging area can be reduced.

Next, FIG. 72 shows a modification of the transmission line section,which is a bifurcated tape-shaped line section (differential line) usedupon input/output of a high-frequency signal among a plurality ofpackages. Two surface layer signal leads 40 g are disposed and surfacelayer GND leads 40 h are respectively disposed on both sides thereof andbetween the two.

In this case, a structure is taken wherein as shown in FIG. 73, one endof the bifurcated tape-shaped line section 45 is connected to onehigh-frequency package 38, whereas other divided ends are respectivelyconnected to discrete other semiconductor packages 44 or the like.

FIGS. 74 and 75 respectively show structures wherein high-frequencypackages 38 with no tape-shaped line sections 40 attached thereto, andother semiconductor packages 44 or the like are first packaged tomounting boards 41 respectively and thereafter a user or the likeconnects the tape-shaped line sections 40 thereto.

In this case, the user is capable of easily turning ON/OFF electricalconnections between the packages by mounting and demounting thetape-shaped line section 40 and changing applications.

(Fourth Embodiment)

FIG. 76 is a perspective view showing one example of a structure of ahigh-frequency package according to a fourth embodiment of the presentinvention, FIG. 77 is a plan view illustrating the structure of thehigh-frequency package shown in FIG. 76, FIG. 78 is a perspective viewshowing a structure of a back side of a frame-shaped transmission linesection mounted to the high-frequency package shown in FIG. 76, FIG. 79is a cross-sectional view depicting one example of a mounting structureof the high-frequency package shown in FIG. 76, FIG. 80 is a plan viewshowing a structure of a high-frequency package illustrative of amodification of the fourth embodiment of the present invention, FIG. 81is s perspective view illustrating the structure of the high-frequencypackage shown in FIG. 80, FIG. 82 is a perspective view showing astructure of a back side of a transmission line section mounted to thehigh-frequency package shown in FIG. 81, FIG. 83 is a plan viewdepicting a structure of a high-frequency package illustrative ofanother modification of the fourth embodiment of the present invention,FIG. 84 is a perspective view showing the structure of thehigh-frequency package shown in FIG. 83, FIG. 85 is a perspective viewillustrating a structure of a back side of a transmission line sectionmounted to the high-frequency package shown in FIG. 84, and FIG. 86 is across-sectional view showing the structure of the high-frequency packageshown in FIG. 83, respectively.

In the fourth embodiment, a transmission line section of ahigh-frequency package (semiconductor device) 47 is disposed so as toprotrude in two opposite directions of a package substrate 4 as shown inFIG. 76. At this time, the transmission line section is provided with aconnecting portion 46 g which protrudes from the transmission linesection in a direction to cross its transmission lines and is formedintegrally with the transmission line section.

Incidentally, the connecting portion 46 g is shaped in a frame formaccording to an outer peripheral shape of the package substrate 4 asshown in FIG. 78. Plate-shaped line portions 46 each corresponding tothe transmission line section protrude in two opposite directions of theframe-shaped connecting portion 46 g and are formed integrally with theconnecting portion 46 g.

Even in the case of the plate-shaped line sections 46, base metal layers(ground conductor layers) 46 b and surface layer metal layers 46 e (seeFIG. 78) are disposed with an insulating layer 46 f formed of apolyimide resin or the like interposed therebetween. Further, each ofthe surface layer metal layers 46 e is a plate-shaped lead (wiring) 46 amade up of a surface layer signal lead (transmission line) 46 c and asurface layer GND lead (transmission line) 46 d.

Incidentally, since the connecting portion 46 g is frame-shaped, asemiconductor chip 2 takes a structure exposed within the frame as shownin FIGS. 76 and 77 when the connecting portion 46 g is mounted on thepackage substrate 4.

FIG. 79 shows the mounting structure wherein the high-frequency package47 is packaged to a mounting board 41. Signal surface layer wirings 4 cof a package substrate 4 in the high-frequency package 47 and theircorresponding surface layer signal leads 46 c of plate-shaped linesections 46, and the surface layer signal leads 46 c of the plate-shapedline sections 46 and their corresponding signal surface layer wirings 41a on the mounting board 41 are respectively electrically connected toone another.

In the high-frequency package 47 shown in FIG. 76, according to thefourth embodiment, the connecting portion 46 g protruded from eachplate-shaped line section 46 assumes the role of reinforcement uponconnection of the plate-shaped line sections 46 and the packagesubstrate 4. Therefore, the connecting portion 46 g is capable ofenhancing the strength of connection between the plate-shaped linesections 46 and the package substrate 4. The larger the area forconnecting the connecting portion 46 g and the package substrate 4 atthis time, the greater the strength of connection between the two.

Further, since the connecting portion 46 formed integrally with theplate-shaped line sections 46 is directly connected to the packagesubstrate 4 in a frame-based large area, heat generated from thesemiconductor chip 2 can be dissipated into the connecting portion 46 gthrough the package substrate 4, so that the radiation of thehigh-frequency package 47 can be enhanced.

Owing to the connection of the plate-shaped line sections 46 each havingthe base metal layer 46 b at a ground potential to the package substrate4, the ground of the high-frequency package 47 can be upgraded and anoise margin can be enhanced.

When the plate-shaped line sections 46 and the connecting portion 46 gare integrally formed, the surface layer signal leads 46 c eachcorresponding to the transmission line, and the surface layer GND leads46 d are formed by etching processing. Further, the central portion ofthe connecting portion 46 g is punched out and thereafter the connectingportion 46 g is formed by press molding. At this time, the bendingaccuracy of each plate-shaped line section 46 can be set to about ±0.05mm owing to the accuracy of a press die.

Incidentally, the connecting portion 46 g may not be necessarily formedin such a frame shape so as to couple the two plate-shaped line sections46 disposed as opposed to each other. The connecting portion 46 g may beone having areas which protrude in a direction to cross transmissionlines of the plate-shaped line sections 46 from the plate-shaped linesections 46 and are connectable to the package substrate 4. Namely, thetwo plate-shaped line sections 46 disposed in an opposing relationshipmay not be necessarily connected to each other.

Next, FIGS. 80 through 82 show a high-frequency package 47 equipped withplate-shaped line sections 46, according to a modification. Transmissionlines are formed in association with four directions of a packagesubstrate 4, and the plate-shaped line sections 46 respectively formedin association with the four sides thereof are brought to an integrallyconnected structure.

Owing to the provision of the structure wherein the plate-shaped linesections 46 corresponding to the four sides of the package substrate 4are respectively connected at the corners in this way, the degree offlatness of each lead can be enhanced.

When the bending accuracy of a press die is about ±0.05 mm, for example,a flatness of 0.05 mm or less can be ensured. Since theintegrally-constructed plate-shaped line sections 46 corresponding tothe four sides are joined to the package substrate 4, the degree offlatness of a ball-electrode mounting surface of the package substrate 4can be set to 0.1 mm or less.

Since the lead flatness can be enhanced, the height-control ballelectrodes 3 (see FIG. 76) become unnecessary. Therefore, thehigh-frequency package 47 can be low priced and its connectionreliability can be enhanced.

FIGS. 83 through 86 show a high-frequency package 47 equipped withplate-shaped line sections 46, according to another modification. Aconnecting portion 46 g is disposed even on a semiconductor chip 2. Asshown in FIG. 86, a back surface 2 b of the semiconductor chip 2 and theconnecting portion 46 g are bonded to each other by an adhesive 48.

Thus, the high-frequency package 47 can be further improved indissipation.

(Fifth Embodiment)

FIG. 87 is a plan view illustrating a structure of a tape-shapedtransmission line section according to a fifth embodiment of the presentinvention, FIG. 88 is a plan view showing a structure of a base metallayer of the tape-shaped transmission line section shown in FIG. 87,FIG. 89 is a plan view depicting a structure of an insulating layer ofthe tape-shaped transmission line section shown in FIG. 87, FIG. 90 is aplan view illustrating a structure of a surface-layer metal layer of thetape-shaped transmission line section shown in FIG. 87, FIG. 91 is aplan view showing a structure of a cover coat layer of the tape-shapedtransmission line section shown in FIG. 87, FIG. 92 is a cross-sectionalview illustrating a structure of a cross-section cut along line A—Ashown in FIG. 87, FIG. 93 is a cross-sectional view depicting astructure of a cross-section cut along line B—B shown in FIG. 87, FIG.94 is a partly cross-sectional view showing a connecting structure ofthe base metal layer of the tape-shaped transmission line section shownin FIG. 87, FIG. 95 is a partly cross-sectional view illustrating aconnecting structure of the surface-layer metal layer of the tape-shapedtransmission line section shown in FIG. 87, FIG. 96 is a plan viewdepicting a structure of a tape-shaped transmission line sectionillustrative of a modification of the fifth embodiment of the presentinvention, FIG. 97 is a plan view showing a structure of a base metallayer of the tape-shaped transmission line section shown in FIG. 96,FIG. 98 is a plan view illustrating a structure of an insulating layerof the tape-shaped transmission line section shown in FIG. 96, FIG. 99is a plan view depicting a structure of a surface-layer metal layer ofthe tape-shaped transmission line section shown in FIG. 96, FIG. 100 isa plan view showing a structure of a cover coat layer of the tape-shapedtransmission line section shown in FIG. 96, FIG. 101 is across-sectional view illustrating a structure of a cross-section cutalong line A—A shown in FIG. 96, FIG. 102 is a cross-sectional viewdepicting a structure of a cross-section cut along line B—B shown inFIG. 96, FIG. 103 is a partly cross-sectional view showing a connectingstructure of a surface-layer metal layer (GND) of the tape-shapedtransmission line section shown in FIG. 96, FIG. 104 is a partlycross-sectional view illustrating a connecting structure of asurface-layer metal layer (signal) of the tape-shaped transmission linesection shown in FIG. 96, FIG. 105 is a cross-sectional view showing astructure of a tape-shaped transmission line section illustrative ofanother modification of the fifth embodiment of the present invention,FIG. 106 is a plan view depicting a structure of a tape-shapedtransmission line section illustrative of a further modification of thefifth embodiment of the present invention, FIG. 107 is a plan viewshowing a structure of a tape-shaped transmission line sectionillustrative of a still further modification of the fifth embodiment ofthe present invention, FIG. 108 is a plan view showing one example of aconnecting structure of the tape-shaped transmission line sectionaccording to the fifth embodiment of the present invention, FIG. 109 isa plan view showing one example illustrative of how a return currentflows in the connecting structure shown in FIG. 108, and FIG. 110 is aplan view showing how a return current flows in a connecting structureof a comparative example with respect to the connecting structure shownin FIG. 108, respectively.

The fifth embodiment describes another embodiment of the tape-shapedtransmission line section.

A tape-shaped line section (transmission line section) 49 shown in FIG.87 is substantially similar in structure to the tape-shaped line section40 described in the third embodiment. However, the tape-shaped linesection 49 is different therefrom in that cut-away portions 40 k arerespectively defined in a base metal layer 40 b, an insulating layer 40c and a cover coat layer 40 e.

A detailed structure of the tape-shaped line section 49 shown in FIG. 87will be described. The tape-shaped line section 49 comprises four layersof a base metal layer 40 b shown in FIG. 88, an insulating layer 40 cshown in FIG. 89, a surface metal layer 40 d shown in FIG. 90 and acover coat layer 40 e shown in FIG. 91. FIG. 92 shows a sectionalstructure at a GND line, and FIG. 93 shows a sectional structure at asignal line.

Incidentally, the base metal layer 40 b shown in FIG. 88, the insulatinglayer 40 c shown in FIG. 89 and the cover coat layer 40 e shown in FIG.91 respectively have cut-away portions 40 k defined in parts of theirends at portions thereof each of which overlaps with a surface layersignal lead 40 g of the surface layer metal layer 40 d.

A longitudinally-extending length of the insulating layer 40 c isshorter than that of the base metal layer 40 b. An end of the base metallayer 40 b is exposed so as to be connectable to a surface layer wiringof a wiring board such as a package substrate 4 or the like.

Further, the surface layer metal layer 40 d comprises a surface layersignal lead 40 g and surface layer GND leads 40 h. The surface layer GNDleads 40 h are shorter than the surface layer signal lead 40 g, and endsof the surface layer GND leads 40 h are covered with the insulatinglayer 40 c.

The cover coat layer 40 e shown in FIG. 91 is disposed on the surfacelayer metal layer 40 d. Further, the base metal layer 40 b and thesurface layer GND leads 40 h of the surface layer metal layer 40 d areelectrically connected by a plurality of vias 40 f. At this time, theplacement pitch between the adjacent vias 40 f is set narrower than atspots other than those in the neighborhood of the cut-away portions 40 kof the respective layers, or successive vias 40 n are provided.

FIGS. 94 and 95 respectively show a state of connection of thetape-shaped line section 49 shown in FIG. 87 to a package substrate 4.FIG. 94 illustrates a state of connection of the base metal layer 40 band GND surface layer wirings 4 h of the package substrate 4 by solder42 (which may be conductive paste or the like). FIG. 95 shows a state ofconnection of the surface layer signal lead 40 g and its correspondingsignal surface layer wiring 4 c on the package substrate 4 by solder 42(which may be conductive paste or the like).

Incidentally, since the longitudinally-extending length of theinsulating layer 40 c is shorter than the length of the base metal layer40 b as shown in FIGS. 88 and 89, the ends of the base metal layer 40 bcan be exposed. Accordingly, the base metal layer 40 b of thetape-shaped line section 49 can be connected to the GND surface layerwirings 4 h of the package substrate 4 as shown in FIG. 94. Thus, a GNDpotential is stabilized so that electric characteristics can beenhanced.

In the fifth embodiment, the base metal layer 40 b, the insulating layer40 c and the cover coat layer 40 e respectively have cut-away portions40 k defined in parts of their ends at portions thereof each of whichoverlaps with the surface layer signal lead 40 g of the surface layermetal layer 40 d.

In addition, the placement pitch between the adjacent vias 40 f is setnarrower than at spots other than those in the neighborhood of thecut-away portions 40 k of the respective layers, or successive vias 40 nare provided. Thus, as shown in FIG. 109, the flow of a return current54 can be made smoother and hence source impedance can be reduced.

A difference in the way of flowing of the return current 54 where thecut-away portions 40 k are defined in the tape-shaped line section 49and no cut-away portions 40 k are not defined therein, will now beexplained.

As shown in FIG. 108, a connecting portion of a surface layer signallead 40 g assumes a coplanar structure 50 where a cut-away portion 40 kis defined in a tape-shaped line section 49 as in the fifth embodiment.However, a GND layer 4 f corresponding to an inner layer is provided onthe substrate side as viewed from the connecting portion. On the otherhand, since a base metal layer 40 b is provided on the lead side asviewed from the connecting portion, both sides of the connecting portionboth result in GND coplanar structures 51.

A tape-shaped line section 49 illustrated in a comparative example ofFIG. 110 is not formed with such a cut-away portion 40 k as shown inFIG. 108. Namely, a connecting portion of a surface layer signal lead 40g results in a GND coplanar structure 51. Thus, when the surface layersignal lead 40 g of the GND coplanar structure 51 is connected to asubstrate, an end portion of a base metal layer 40 b is placed on theback surface side of the surface layer signal lead 40 g, and a signalsurface layer wiring 4 c is formed at a portion which overlaps with thesurface layer signal lead 40 g. Therefore, the connections between thebase metal layer 40 b and GND surface layer wirings 4 h are made only inthe edge neighborhood of an end of the base metal layer 40 b.

Therefore, for example, a return current 54 which has flowed immediatelybelow the corresponding wiring from the lead side to the substrate,abruptly changes its direction in the edge neighborhood (vicinity of Q)of the base metal layer 40 b (GND) and enters into the substrate side.

Thus, since there is a possibility that the moving distance of thereturn current 54 becomes long, thus leading to an increase in sourceimpedance, this is not desirable.

On the other hand, when the cut-away portion 40 k is provided as shownin FIG. 109, the return current 54 that has flowed immediately below thewiring from the lead side to the substrate, gently changes itsdirection. Therefore, an increase in source impedance at an end (in thevicinity of P) of a base metal layer 40 b (GND) is reduced as comparedwith FIG. 110.

Thus, the formation of the GND coplanar structure 51+coplanar structure50+GND coplanar structure 51 by the provision of the cut-away portion 40k for the tape-shaped line section 49 enables a further reduction intransmission loss of a signal of a high frequency. Further, the mountingpitch between the adjacent vias 40 f is set narrower than at spots otherthan those in the neighborhood of the cut-away portion 40 k, orsuccessive vias 40 n are provided. Thus, the flow of the return current54 can be made smoother so that source impedance can be further reduced,thus making it possible to further improve electric characteristics.

Next, FIG. 96 shows a tape-shaped line section 49 illustrative of themodification of the fifth embodiment. Configurations of the tape-shapedline section 49 and its sectional structures are respectivelyillustrated in FIGS. 97 through 102.

Incidentally, the tape-shaped line section 49 of the modification shownin FIG. 96 is substantially similar in structure to the tape-shaped linesection 49 shown in FIG. 87 and formed with a cut-away portion 40 k.However, the length of each surface layer GND lead 40 h in a surfacelayer metal layer 40 d is longer than that of a base metal layer 40 b.

In this case, as shown in FIG. 103, the surface layer GND leads 40 h ofthe surface metal layer 40 d, and their corresponding GND surface layerwirings 4 h of a package substrate 4 are connected to one another bymeans of solder 42 or conductive paste or the like. On the other hand,as shown in FIG. 104, a surface layer signal lead 40 g of the surfacelayer metal layer 40 d and its corresponding signal surface layer wiring4 c of the package substrate 4 are connected to each other by solder 42or conductive paste or the like.

Now, as shown in FIGS. 103 and 104, a semiconductor chip 2 is mounted onthe package substrate 4 with solder ball electrodes 5 interposedtherebetween. Each of the GND surface layer wirings 4 h and apredetermined solder bump electrode 5, and the signal surface layerwiring 4 c and a predetermined bump electrode 5 are respectivelyconnected to one another.

Incidentally, assuming that in each of the package substrates 4 shown inFIGS. 103 and 104, an area (corresponding to an area in which no GNDlayer 4 f is formed) up to a substrate end on the left side toward fromthe GND layer 4 f in each drawing is defined as a first area, and anarea in which the GND layer 4 f is formed, is defined as a second area,no other wiring layer is formed between GND surface layer wirings 4 hand the GND layer 4 f in the second area. Further, no GND layer 4 f isformed below the GND surface layer wirings 4 h and the signal surfacelayer wiring 4 c formed in the first area.

Thus, since the cut-away portion 40 k is formed even in the case of thetape-shaped line section 49 shown in FIG. 96, a GND coplanar structure51+coplanar structure 50+GND coplanar structure 51 can be brought about.In a manner similar to the tape-shaped line section 49 shown in FIG. 87,a reduction in transmission loss of a signal of a high frequency can beachieved. As a result, an improvement in electric characteristic can beachieved.

Incidentally, when it is possible to form the base metal layer 40 bthick fully, the tape-shaped line section 49 shown in FIG. 87 is capableof enhancing the strength of GND connection.

Next, a tape-shaped line section 52 illustrative of another modificationshown in FIG. 105 is one wherein other metal layer 40 j made up of awiring pattern or the like is provided between a base metal layer 40 band an insulating layer 40 c, and a surface protective layer 40 m isformed on the surface of the base metal layer 40 b.

Since the metal layer 40 j made up of the wiring pattern and high inmetal purity can be formed in this case, source impedance can be furtherreduced, and electric characteristics can be enhanced.

Incidentally, while the fifth embodiment has described the case in whichone signal line is disposed in each of the tape-shaped line sections 49and 52 and GND lines are formed on both sides one by one as threewirings in total, the numbers of signal lines and GND lines arerespectively not limited to the above. Therefore, two surface layersignal leads 40 g may be provided as shown in FIGS. 106 and 107. Atape-shaped line section 53 shown in FIG. 106 is one wherein two surfacelayer signal leads 40 g are disposed between the surface layer GND leads40 h at both ends. A tape-shaped line section 55 shown in FIG. 107 isone wherein surface layer GND leads 40 h are disposed on both sides oftwo surface layer signal leads 40 g respectively, and a surface layerGND lead 40 h is disposed even between the two surface layer signalleads 40 g. The two surface layer signal leads 40 g and the threesurface layer GND leads 40 h are provided.

Since the tape-shaped line section 53 and the tape-shaped line section55 are also provided with cut-away portions 40 k, an advantage similarto the tape-shaped line section 49 shown in FIG. 87 can be obtained.

While the invention made above by the present inventors has beendescribed specifically based on the illustrated embodiments, the presentinvention is not limited to the embodiments. It is needless to say thatmany changes can be made thereto within the scope not departing from thesubstance thereof.

While each of the first through fifth embodiments has described the casein which the semiconductor device is of the ball grid array typesemiconductor package, for example, the semiconductor device may be anLGA (Land Grid Array) or the like, for example, if one having astructure wherein a plurality of external connecting terminals aredisposed within a plane of a package substrate, is adopted.

Further, while each of the first through fifth embodiments has describedthe case in which the semiconductor chip 2 is flip-chip connected to thepackage substrate 4, the method of connecting the semiconductor chip 2and the package substrate 4 is not limited to such a flip-chipconnection. It may be ribbon bonding using flat plate-shaped metalwires, etc.

Advantageous effects obtained by a typical one of the inventionsdisclosed in the present application will be described in brief asfollows:

A high-frequency signal is transmitted via a transmission line sectionconnected to each surface layer wiring on a wiring board. Therefore, atransmission loss in high frequency is reduced and thereby its signalcan be transmitted. As a result, a high-quality high-frequency signalcan be transmitted.

1. A semiconductor device, comprising: a wiring board formed with a surface layer wiring; a semiconductor chip mounted on the wiring board and directly connected to the surface layer wiring only through a solder bump electrode sandwiched between the semiconductor chip and the wiring board; a plurality of external connecting terminals provided within either a main surface of the wiring board or a back surface thereof opposite to the main surface; and a transmission line section connected to the surface layer wiring of the wiring board, wherein at least either input or output of a signal to the semiconductor chip is performed through the transmission line section.
 2. The semiconductor device according to claim 1, wherein the transmission line section is a coaxial cable, and a core line of the coaxial cable is connected to the surface layer wiring.
 3. The semiconductor device according to claim 1, wherein the transmission line section has plate-shaped leads and each of the plate-shaped leads is connected to the surface layer wiring.
 4. The semiconductor device according to claim 3, wherein the transmission line section is a tape-shaped member.
 5. The semiconductor device according to claim 4, wherein a connecting portion protrudes from the transmission line section in a direction to cross transmission lines of the transmission line section and is provided integrally with the transmission line section.
 6. The semiconductor device according to claim 5, wherein the connecting portion is arranged over the semiconductor chip.
 7. The semiconductor device according to claim 4, wherein the connecting portion has wirings and a ground conductor layer disposed through the wirings and an insulating layer.
 8. The semiconductor device according to claim 1, which is a ball grid array having a plurality of bump electrodes as the external connecting terminals.
 9. The semiconductor device according to claim 1, which is a land grid array having a plurality of land electrodes as the external connecting terminals.
 10. The semiconductor device according to claim 1, wherein the semiconductor chip has a circuit which divides an input signal of a first frequency into a plurality of signals each having a second frequency smaller than the first frequency and outputs the same, or a circuit which combines a plurality of input signals each having a third frequency into a signal of a fourth frequency larger than the third frequency and outputs the same.
 11. The semiconductor device according to claim 10, wherein the first and fourth frequencies are respectively 1 GHz or more.
 12. The semiconductor device according to claim 1, wherein the semiconductor chip is mounted on the wiring board with a plurality of solder bump electrodes interposed therebetween.
 13. A semiconductor device, comprising: a wiring board formed with a surface layer wiring; a semiconductor chip mounted on the wiring board and directly connected to the surface layer wiring only through a solder bump electrode sandwiched between the semiconductor chip and the wiring board; a plurality of external connecting terminals provided within either a main surface of the wiring board or a back surface thereof opposite to the main surface; and a transmission line section having plate-shaped leads connected to wirings of the wiring board, wherein at least either input or output of a signal to the semiconductor chip is performed through the plate-shaped leads.
 14. A semiconductor device, comprising: a wiring board having first and second areas; surface layer wirings formed in the first and second areas over the wiring board; a semiconductor chip mounted on the wiring board and directly connected to the surface layer wirings only through a solder bump electrode sandwiched between the semiconductor chip and the wiring board; and transmission lines connected to the wirings in the first area, wherein at least either input or output of a signal to the semiconductor chip is performed through the transmission lines, and wherein GND layers are formed below the wirings disposed in the second area of the wiring board, and the GND layers are not formed below the wirings disposed in the first area.
 15. The semiconductor device according to claim 14, wherein other wiring layers are not formed between the wirings in the second area and the GND layers.
 16. The semiconductor device according to claim 15, wherein the transmission lines in the first area constitute a coplanar structure and the wirings in the second area constitute a ground coplanar structure. 